From 32343d9dc41fdd075265d0b47e3d89abd38d192f Mon Sep 17 00:00:00 2001
From: samuelbles07 <samuelbles07@gmail.com>
Date: Fri, 7 Aug 2026 01:05:52 +0700
Subject: [PATCH 1/3] feat(go): add cloud GPS test trigger

---
 products/go/ARCHITECTURE.md                 |  5 +-
 products/go/docs/cloud_service.md           | 24 +++++----
 products/go/docs/hardware_test.md           |  6 +++
 products/go/main/go_cloud.cpp               |  6 +++
 products/go/main/go_cloud_types.h           |  1 +
 products/go/main/go_orchestrator.cpp        |  9 ++++
 products/go/tests/go_cloud.tests.cpp        | 11 ++--
 products/go/tests/go_orchestrator.tests.cpp | 59 ++++++++++++++++++++-
 8 files changed, 104 insertions(+), 17 deletions(-)

diff --git a/products/go/ARCHITECTURE.md b/products/go/ARCHITECTURE.md
index ee1a116..cd39ec5 100644
--- a/products/go/ARCHITECTURE.md
+++ b/products/go/ARCHITECTURE.md
@@ -906,8 +906,9 @@ snapshot ownership, queue semantics, and lifecycle details.
 - Cloud Fetch can update PM standard, temperature unit, `abcDays`, and PM2.5,
   temperature, and humidity corrections. It does not own `cloudConnection` or
   `configurationControl`, even if those fields appear in a response
-- True `co2CalibrationRequested` and `ledTestRequested` Fetch fields are carried
-  outside persistent settings and dispatch calibration or the LED diagnostic
+- True `co2CalibrationRequested`, `ledTestRequested`, and `gpsTestRequested`
+  Fetch fields are carried outside persistent settings and dispatch calibration,
+  the LED diagnostic, or direct navigation to the live GPS Test screen
 
 `configurationControl` governs the two competing remote config sources:
 
diff --git a/products/go/docs/cloud_service.md b/products/go/docs/cloud_service.md
index 357944a..f41cdd6 100644
--- a/products/go/docs/cloud_service.md
+++ b/products/go/docs/cloud_service.md
@@ -170,6 +170,7 @@ and queues a value-only `FetchConfigEventPayload`. Supported fields map into
 | `buzzerEnabled` | Boolean | `buzzer_enabled` |
 | `co2CalibrationRequested` | Boolean | One-shot CO2 calibration request; not persisted |
 | `ledTestRequested` | Boolean | One-shot LED diagnostic request; not persisted |
+| `gpsTestRequested` | Boolean | One-shot GPS test screen request; not persisted |
 
 Sensor and correction fields are:
 
@@ -199,12 +200,15 @@ malformed roots, and trailing non-whitespace data produce an empty update mask.
 
 `co2CalibrationRequested: true` queues background CO2 calibration through the
 sensor producer. `ledTestRequested: true` then runs the three-second LED
-diagnostic. If both are true, calibration is queued before the blocking LED
-test. `false`, a missing field, or a non-boolean value does nothing. The parser
-stores both values directly in `FetchConfigEventPayload`; they never enter
-`GoConfigUpdate`, settings, or NVS. The firmware performs no edge detection
-because the backend returns `true` once per request and then returns `false`
-until another request is made.
+diagnostic. `gpsTestRequested: true` finally opens the live GPS Test screen and
+starts its receiver, fast-posting, and TTFF behavior. This ordering lets all
+three actions run when one response requests them. A GPS trigger is ignored if
+the Peripheral or Accelerometer test is active, and is a no-op if the GPS Test
+screen is already open. `false`, a missing field, or a non-boolean value does
+nothing. The parser stores the action values directly in
+`FetchConfigEventPayload`; they never enter `GoConfigUpdate`, settings, or NVS.
+The firmware performs no edge detection because the backend returns `true` once
+per request and then returns `false` until another request is made.
 
 Cloud result delivery is best-effort. A full central queue drops the zero-wait
 event, so no update is applied; the next periodic FETCH is the next retry
@@ -212,10 +216,10 @@ opportunity.
 
 The orchestrator rechecks `configuration_control` when it consumes the result.
 If control changes to `Local` while HTTP is in flight, the successful event is
-discarded without persistence, runtime changes, calibration, or an LED
-diagnostic. Re-enabling Cloud/Both calls `set_config_fetch_enabled(true)`, making
-the next FETCH immediately due when the task is armed and cloud transport is
-enabled.
+discarded without persistence, runtime changes, calibration, an LED diagnostic,
+or GPS Test navigation. Re-enabling Cloud/Both calls
+`set_config_fetch_enabled(true)`, making the next FETCH immediately due when the
+task is armed and cloud transport is enabled.
 
 ### OTA Interaction
 
diff --git a/products/go/docs/hardware_test.md b/products/go/docs/hardware_test.md
index 27515a8..56b5e79 100644
--- a/products/go/docs/hardware_test.md
+++ b/products/go/docs/hardware_test.md
@@ -111,6 +111,12 @@ LED marks the fix. The screen shows TTFF (`mm:ss`), fix type, satellites, HDOP,
 latitude/longitude, and UTC. On exit the posting cadence and back LED are
 restored, and the receiver is stopped only if the test ungated it.
 
+A cloud Fetch response can set `gpsTestRequested: true` to open this screen
+without manual Settings navigation. The orchestrator handles it after the CO2
+calibration and LED-test action flags from the same response. It ignores the
+request while the Peripheral or Accelerometer test is active and treats it as a
+no-op when the GPS Test screen is already open.
+
 See [`gps_service.md`](gps_service.md) for the receiver lifecycle.
 
 ### Accelerometer Test
diff --git a/products/go/main/go_cloud.cpp b/products/go/main/go_cloud.cpp
index 75f1ac1..b9af958 100644
--- a/products/go/main/go_cloud.cpp
+++ b/products/go/main/go_cloud.cpp
@@ -58,6 +58,7 @@ constexpr const char *JSON_TOUCH_LED_INTENSITY = "touchLedIntensity";
 constexpr const char *JSON_BUZZER_ENABLED = "buzzerEnabled";
 constexpr const char *JSON_CO2_CALIBRATION_REQUESTED = "co2CalibrationRequested";
 constexpr const char *JSON_LED_TEST_REQUESTED = "ledTestRequested";
+constexpr const char *JSON_GPS_TEST_REQUESTED = "gpsTestRequested";
 constexpr const char *JSON_ABC_DAYS = "abcDays";
 constexpr const char *JSON_TVOC_LEARNING_OFFSET = "tvocLearningOffset";
 constexpr const char *JSON_NOX_LEARNING_OFFSET = "noxLearningOffset";
@@ -377,6 +378,11 @@ FetchConfigEventPayload parse_cloud_config(const char *buffer, size_t bytes) {
     (void)parse_bool(led_test_requested, JSON_LED_TEST_REQUESTED, payload.led_test_requested);
   }
 
+  const cJSON *gps_test_requested = cJSON_GetObjectItemCaseSensitive(root, JSON_GPS_TEST_REQUESTED);
+  if (gps_test_requested != nullptr) {
+    (void)parse_bool(gps_test_requested, JSON_GPS_TEST_REQUESTED, payload.gps_test_requested);
+  }
+
   const cJSON *abc_days = cJSON_GetObjectItemCaseSensitive(root, JSON_ABC_DAYS);
   if (abc_days != nullptr && parse_co2_abc_days(abc_days, update.co2_abc_days)) {
     update.update_mask |= static_cast<uint32_t>(GoConfigField::Co2AbcDays);
diff --git a/products/go/main/go_cloud_types.h b/products/go/main/go_cloud_types.h
index 3bdc961..9a4f29e 100644
--- a/products/go/main/go_cloud_types.h
+++ b/products/go/main/go_cloud_types.h
@@ -26,6 +26,7 @@ struct FetchConfigEventPayload {
   GoConfigUpdate update{};
   bool co2_calibration_requested = false;
   bool led_test_requested = false;
+  bool gps_test_requested = false;
 };
 
 static_assert(std::is_trivially_copyable<FetchConfigEventPayload>::value,
diff --git a/products/go/main/go_orchestrator.cpp b/products/go/main/go_orchestrator.cpp
index a78ba5c..0f2ac28 100644
--- a/products/go/main/go_orchestrator.cpp
+++ b/products/go/main/go_orchestrator.cpp
@@ -770,6 +770,15 @@ void Orchestrator::handle_cloud_action_requests(const FetchConfigEventPayload &p
   if (payload.led_test_requested) {
     run_led_test();
   }
+  if (payload.gps_test_requested) {
+    const Screen current_screen = _svc.ui_manager.current_screen();
+    if (current_screen == Screen::PeripheralTest || current_screen == Screen::AccelTest) {
+      AG_LOGW(TAG, "GPS test trigger ignored: another hardware test is active");
+    } else if (current_screen != Screen::GpsTest) {
+      _svc.ui_manager.set_screen(Screen::GpsTest);
+      start_gps_test();
+    }
+  }
 }
 
 void Orchestrator::on_local_api_request(uint32_t event_epoch) {
diff --git a/products/go/tests/go_cloud.tests.cpp b/products/go/tests/go_cloud.tests.cpp
index cfd76ab..54ee818 100644
--- a/products/go/tests/go_cloud.tests.cpp
+++ b/products/go/tests/go_cloud.tests.cpp
@@ -374,6 +374,7 @@ TEST_CASE("FETCH forwards AgClientResult into FetchConfigResult event", "[CloudS
   REQUIRE(f.mock_rtos.last_event.fetch_config.update.update_mask == 0);
   REQUIRE_FALSE(f.mock_rtos.last_event.fetch_config.co2_calibration_requested);
   REQUIRE_FALSE(f.mock_rtos.last_event.fetch_config.led_test_requested);
+  REQUIRE_FALSE(f.mock_rtos.last_event.fetch_config.gps_test_requested);
   REQUIRE(wake == 0);
 }
 
@@ -456,7 +457,7 @@ TEST_CASE("FETCH parses supported root scalars and ignores cloud policy fields",
           "[CloudService][fetch][config]") {
   CloudFixture f;
   const char body[] =
-      R"({"pmStandard":"us-aqi","temperatureUnit":"f","measurementInterval":3600,"gpsMode":"always","frontLedBrightness":0,"backLedBrightness":3,"touchLedIntensity":2,"buzzerEnabled":true,"co2CalibrationRequested":true,"ledTestRequested":true,"disableCloudConnection":true,"configurationControl":"local","corrections":[]})";
+      R"({"pmStandard":"us-aqi","temperatureUnit":"f","measurementInterval":3600,"gpsMode":"always","frontLedBrightness":0,"backLedBrightness":3,"touchLedIntensity":2,"buzzerEnabled":true,"co2CalibrationRequested":true,"ledTestRequested":true,"gpsTestRequested":true,"disableCloudConnection":true,"configurationControl":"local","corrections":[]})";
   cloud_spy::fetch_body_to_write = body;
   cloud_spy::fetch_bytes_to_write = std::strlen(body);
 
@@ -487,24 +488,27 @@ TEST_CASE("FETCH parses supported root scalars and ignores cloud policy fields",
   REQUIRE(update.buzzer_enabled);
   REQUIRE(f.mock_rtos.last_event.fetch_config.co2_calibration_requested);
   REQUIRE(f.mock_rtos.last_event.fetch_config.led_test_requested);
+  REQUIRE(f.mock_rtos.last_event.fetch_config.gps_test_requested);
   REQUIRE_FALSE(update.disable_cloud);
   REQUIRE(update.configuration_control == ConfigurationControl::Both);
   REQUIRE_FALSE(has_go_config_field(update.update_mask, GoConfigField::Pm25Correction));
 
-  const char cleared_body[] = R"({"co2CalibrationRequested":false,"ledTestRequested":false})";
+  const char cleared_body[] =
+      R"({"co2CalibrationRequested":false,"ledTestRequested":false,"gpsTestRequested":false})";
   cloud_spy::fetch_body_to_write = cleared_body;
   cloud_spy::fetch_bytes_to_write = std::strlen(cleared_body);
   A::set_fetch_due(f.cloud, 0);
   A::run_once(f.cloud, 1500);
   REQUIRE_FALSE(f.mock_rtos.last_event.fetch_config.co2_calibration_requested);
   REQUIRE_FALSE(f.mock_rtos.last_event.fetch_config.led_test_requested);
+  REQUIRE_FALSE(f.mock_rtos.last_event.fetch_config.gps_test_requested);
 }
 
 TEST_CASE("FETCH rejects malformed device settings independently",
           "[CloudService][fetch][config]") {
   CloudFixture f;
   const char body[] =
-      R"({"temperatureUnit":"c","measurementInterval":0,"gpsMode":"ALWAYS","frontLedBrightness":4,"backLedBrightness":-1,"touchLedIntensity":3,"buzzerEnabled":"true","co2CalibrationRequested":"true","ledTestRequested":1})";
+      R"({"temperatureUnit":"c","measurementInterval":0,"gpsMode":"ALWAYS","frontLedBrightness":4,"backLedBrightness":-1,"touchLedIntensity":3,"buzzerEnabled":"true","co2CalibrationRequested":"true","ledTestRequested":1,"gpsTestRequested":"true"})";
   cloud_spy::fetch_body_to_write = body;
   cloud_spy::fetch_bytes_to_write = std::strlen(body);
 
@@ -524,6 +528,7 @@ TEST_CASE("FETCH rejects malformed device settings independently",
   REQUIRE_FALSE(has_go_config_field(update.update_mask, GoConfigField::BuzzerEnabled));
   REQUIRE_FALSE(f.mock_rtos.last_event.fetch_config.co2_calibration_requested);
   REQUIRE_FALSE(f.mock_rtos.last_event.fetch_config.led_test_requested);
+  REQUIRE_FALSE(f.mock_rtos.last_event.fetch_config.gps_test_requested);
 }
 
 TEST_CASE("FETCH parses valid ABC days and rejects malformed values independently",
diff --git a/products/go/tests/go_orchestrator.tests.cpp b/products/go/tests/go_orchestrator.tests.cpp
index 4e9332b..b8b3596 100644
--- a/products/go/tests/go_orchestrator.tests.cpp
+++ b/products/go/tests/go_orchestrator.tests.cpp
@@ -2935,7 +2935,7 @@ TEST_CASE("dispatch: cloud applies shared config fields and ignores policy field
   CHECK(test_spy::cloud_set_fetch_enabled_count == 0);
 }
 
-TEST_CASE("dispatch: Cloud Fetch actions queue calibration before the LED test",
+TEST_CASE("dispatch: Cloud Fetch actions run calibration and LED test before opening GPS test",
           "[Orchestrator][dispatch][cloud][action]") {
   TestFixture f;
   auto orch = f.make_orchestrator();
@@ -2945,16 +2945,24 @@ TEST_CASE("dispatch: Cloud Fetch actions queue calibration before the LED test",
   evt.fetch_config.result = static_cast<CloudResultByte>(AgClientResult::Ok);
   evt.fetch_config.co2_calibration_requested = true;
   evt.fetch_config.led_test_requested = true;
+  evt.fetch_config.gps_test_requested = true;
 
   bool calibration_queued_before_led_test = false;
+  bool gps_closed_during_led_test = false;
   REQUIRE_CALL(f.mock_rtos, delay_ms_impl(3000))
-      .LR_SIDE_EFFECT(calibration_queued_before_led_test = test_spy::co2_calibration_requested);
+      .LR_SIDE_EFFECT(calibration_queued_before_led_test = test_spy::co2_calibration_requested;
+                      gps_closed_during_led_test =
+                          f.ui_manager.current_screen() != Screen::GpsTest;);
   A::dispatch(orch, evt);
 
   CHECK(test_spy::co2_calibration_requested);
   CHECK(calibration_queued_before_led_test);
+  CHECK(gps_closed_during_led_test);
   CHECK(test_spy::led_back_play_count == 1);
   CHECK(test_spy::led_touch_all_on_seen);
+  CHECK(f.ui_manager.current_screen() == Screen::GpsTest);
+  CHECK(test_spy::gps_started);
+  CHECK(test_spy::gps_posting_interval_ms == 1000);
 }
 
 TEST_CASE("dispatch: Cloud Fetch actions respect local-only control",
@@ -2968,11 +2976,58 @@ TEST_CASE("dispatch: Cloud Fetch actions respect local-only control",
   evt.fetch_config.result = static_cast<CloudResultByte>(AgClientResult::Ok);
   evt.fetch_config.co2_calibration_requested = true;
   evt.fetch_config.led_test_requested = true;
+  evt.fetch_config.gps_test_requested = true;
   A::dispatch(orch, evt);
 
   CHECK_FALSE(test_spy::co2_calibration_requested);
   CHECK(test_spy::led_back_play_count == 0);
   CHECK_FALSE(test_spy::led_touch_all_on_seen);
+  CHECK(f.ui_manager.current_screen() == Screen::Home);
+  CHECK_FALSE(test_spy::gps_started);
+}
+
+TEST_CASE("dispatch: Cloud GPS test trigger does not interrupt another hardware test",
+          "[Orchestrator][dispatch][cloud][action][gps-test]") {
+  TestFixture f;
+  auto orch = f.make_orchestrator();
+
+  Event evt{};
+  evt.type = EventType::FetchConfigResult;
+  evt.fetch_config.result = static_cast<CloudResultByte>(AgClientResult::Ok);
+  evt.fetch_config.gps_test_requested = true;
+
+  SECTION("peripheral test") {
+    f.ui_manager.set_screen(Screen::PeripheralTest);
+    A::dispatch(orch, evt);
+
+    CHECK(f.ui_manager.current_screen() == Screen::PeripheralTest);
+    CHECK_FALSE(test_spy::gps_started);
+  }
+
+  SECTION("accelerometer test") {
+    f.ui_manager.set_screen(Screen::AccelTest);
+    A::dispatch(orch, evt);
+
+    CHECK(f.ui_manager.current_screen() == Screen::AccelTest);
+    CHECK_FALSE(test_spy::gps_started);
+  }
+}
+
+TEST_CASE("dispatch: Cloud GPS test trigger is idempotent while GPS test is open",
+          "[Orchestrator][dispatch][cloud][action][gps-test]") {
+  TestFixture f;
+  auto orch = f.make_orchestrator();
+  f.ui_manager.set_screen(Screen::GpsTest);
+
+  Event evt{};
+  evt.type = EventType::FetchConfigResult;
+  evt.fetch_config.result = static_cast<CloudResultByte>(AgClientResult::Ok);
+  evt.fetch_config.gps_test_requested = true;
+  A::dispatch(orch, evt);
+
+  CHECK(f.ui_manager.current_screen() == Screen::GpsTest);
+  CHECK_FALSE(test_spy::gps_started);
+  CHECK(test_spy::gps_posting_interval_ms == 0);
 }
 
 TEST_CASE("dispatch: cloud ABC days persists before requesting sensor application",

From c46ec843bb4ab7f93d8d684f5340265a2f315ba6 Mon Sep 17 00:00:00 2001
From: samuelbles07 <samuelbles07@gmail.com>
Date: Fri, 7 Aug 2026 01:32:44 +0700
Subject: [PATCH 2/3] feat(go): add local GPS test action

---
 .../services/local_server.cpp                 |  7 ++++++
 .../services/local_server.h                   |  2 +-
 .../tests/fake_providers.h                    | 11 +++++++-
 .../tests/handler.tests.cpp                   | 15 ++++++++++-
 .../types/local_server_result.h               |  2 +-
 docs/local_http_api.md                        |  4 +++
 products/go/ARCHITECTURE.md                   |  5 ++--
 products/go/docs/hardware_test.md             | 11 ++++----
 products/go/docs/local_server.md              |  7 ++++++
 products/go/feature_overview.md               |  7 +++---
 products/go/main/go_local_api.cpp             |  3 ++-
 products/go/main/go_orchestrator.cpp          | 25 +++++++++++++------
 products/go/main/go_orchestrator.h            |  3 +++
 products/go/tests/go_local_api.tests.cpp      | 10 +++++++-
 products/go/tests/go_orchestrator.tests.cpp   | 14 +++++++++++
 products/go/tests/go_wifi.tests.cpp           | 20 ++++++++-------
 .../tests/local-server-integration/README.md  |  9 ++++---
 .../local-server-integration/ago_local_api.py |  1 +
 .../local-server-integration/test_actions.py  |  4 +++
 .../local-server-integration/test_ota.py      | 13 ++++++++++
 products/reference/main/test_local_server.cpp |  3 +++
 products/reference/main/test_local_server.h   |  1 +
 22 files changed, 142 insertions(+), 35 deletions(-)

diff --git a/components/airgradient-local-server/services/local_server.cpp b/components/airgradient-local-server/services/local_server.cpp
index fe868e3..4e33698 100644
--- a/components/airgradient-local-server/services/local_server.cpp
+++ b/components/airgradient-local-server/services/local_server.cpp
@@ -24,6 +24,7 @@ constexpr const char *PATH_MEASURES = "/api/v1/measures";
 constexpr const char *PATH_CONFIG = "/api/v1/config";
 constexpr const char *PATH_ACTION_CALIBRATE_CO2 = "/api/v1/actions/calibrate-co2";
 constexpr const char *PATH_ACTION_TEST_LEDS = "/api/v1/actions/test-leds";
+constexpr const char *PATH_ACTION_TEST_GPS = "/api/v1/actions/test-gps";
 
 // Includes headroom for a fully escaped MAX_UNKNOWN_KEY field.
 constexpr size_t ERROR_BUF_SIZE = 512;
@@ -167,6 +168,12 @@ bool LocalServer::begin() {
                        _handle_action(ActionId::TestLeds, q, r);
                      });
     }
+    if (ok) {
+      ok = _register(HttpMethod::Post, PATH_ACTION_TEST_GPS,
+                     [this](const HttpRequest &q, HttpResponse &r) {
+                       _handle_action(ActionId::TestGps, q, r);
+                     });
+    }
   }
 
   if (!ok) {
diff --git a/components/airgradient-local-server/services/local_server.h b/components/airgradient-local-server/services/local_server.h
index 4c99b57..86ed3e0 100644
--- a/components/airgradient-local-server/services/local_server.h
+++ b/components/airgradient-local-server/services/local_server.h
@@ -100,7 +100,7 @@ class LocalServer {
   ConfigAccess _config_access;
   ActionHandler *_actions;
 
-  static constexpr size_t MAX_OWNED_ROUTES = 5; // measures + config x2 + 2 actions
+  static constexpr size_t MAX_OWNED_ROUTES = 6; // measures + config x2 + 3 actions
   OwnedRoute _routes[MAX_OWNED_ROUTES] = {};
   size_t _route_count = 0;
   bool _begun = false;
diff --git a/components/airgradient-local-server/tests/fake_providers.h b/components/airgradient-local-server/tests/fake_providers.h
index ee89498..aa851ca 100644
--- a/components/airgradient-local-server/tests/fake_providers.h
+++ b/components/airgradient-local-server/tests/fake_providers.h
@@ -113,13 +113,22 @@ class FakeActionHandler : public ActionHandler {
 public:
   ActionResult result_calibrate{ActionStatus::Dispatched};
   ActionResult result_test_leds{ActionStatus::Dispatched};
+  ActionResult result_test_gps{ActionStatus::Dispatched};
   ActionId last_action = ActionId::CalibrateCo2;
   bool triggered = false;
 
   ActionResult trigger(ActionId action) override {
     triggered = true;
     last_action = action;
-    return action == ActionId::CalibrateCo2 ? result_calibrate : result_test_leds;
+    switch (action) {
+    case ActionId::CalibrateCo2:
+      return result_calibrate;
+    case ActionId::TestLeds:
+      return result_test_leds;
+    case ActionId::TestGps:
+      return result_test_gps;
+    }
+    return {ActionStatus::NotSupported};
   }
 };
 
diff --git a/components/airgradient-local-server/tests/handler.tests.cpp b/components/airgradient-local-server/tests/handler.tests.cpp
index 6201d05..63da950 100644
--- a/components/airgradient-local-server/tests/handler.tests.cpp
+++ b/components/airgradient-local-server/tests/handler.tests.cpp
@@ -21,6 +21,7 @@ constexpr const char *MEASURES = "/api/v1/measures";
 constexpr const char *CONFIG = "/api/v1/config";
 constexpr const char *CALIBRATE_CO2 = "/api/v1/actions/calibrate-co2";
 constexpr const char *TEST_LEDS = "/api/v1/actions/test-leds";
+constexpr const char *TEST_GPS = "/api/v1/actions/test-gps";
 
 std::string body_string(const HttpResponse &resp) {
   return std::string(static_cast<const char *>(resp.body_data()), resp.body_size());
@@ -354,9 +355,10 @@ TEST_CASE("actions register all catalog routes and map results", "[handler][acti
   LocalServer ls(server, {measures, nullptr, ConfigAccess::Disabled, &actions});
   REQUIRE(ls.begin());
 
-  // Both catalog actions get a route, regardless of model support.
+  // Every catalog action gets a route, regardless of model support.
   REQUIRE(server.has_route(HttpMethod::Post, CALIBRATE_CO2));
   REQUIRE(server.has_route(HttpMethod::Post, TEST_LEDS));
+  REQUIRE(server.has_route(HttpMethod::Post, TEST_GPS));
 
   SECTION("Dispatched -> 200 empty body") {
     actions.result_calibrate = {ActionStatus::Dispatched};
@@ -379,6 +381,16 @@ TEST_CASE("actions register all catalog routes and map results", "[handler][acti
     REQUIRE(error_code(resp) == "forbidden");
   }
 
+  SECTION("GPS test dispatches the catalog action") {
+    actions.result_test_gps = {ActionStatus::Dispatched};
+    TestHttpRequest req(HttpMethod::Post, TEST_GPS);
+    HttpResponse resp;
+    REQUIRE(server.invoke(HttpMethod::Post, TEST_GPS, req, resp));
+    REQUIRE(resp.status == HttpStatus::Ok);
+    REQUIRE(resp.body_size() == 0);
+    REQUIRE(actions.last_action == ActionId::TestGps);
+  }
+
   SECTION("NotSupported -> 404 not_found") {
     actions.result_test_leds = {ActionStatus::NotSupported};
     TestHttpRequest req(HttpMethod::Post, TEST_LEDS);
@@ -407,6 +419,7 @@ TEST_CASE("no action handler leaves action routes unregistered", "[handler][acti
   REQUIRE(ls.begin());
   REQUIRE_FALSE(server.has_route(HttpMethod::Post, CALIBRATE_CO2));
   REQUIRE_FALSE(server.has_route(HttpMethod::Post, TEST_LEDS));
+  REQUIRE_FALSE(server.has_route(HttpMethod::Post, TEST_GPS));
 }
 
 TEST_CASE("begin is idempotent", "[lifecycle]") {
diff --git a/components/airgradient-local-server/types/local_server_result.h b/components/airgradient-local-server/types/local_server_result.h
index 3fcde55..5bac496 100644
--- a/components/airgradient-local-server/types/local_server_result.h
+++ b/components/airgradient-local-server/types/local_server_result.h
@@ -68,7 +68,7 @@ struct ConfigSubmitResult {
   ConfigFieldId field = ConfigFieldId::None;
 };
 
-enum class ActionId : uint8_t { CalibrateCo2, TestLeds };
+enum class ActionId : uint8_t { CalibrateCo2, TestLeds, TestGps };
 
 enum class ActionStatus : uint8_t {
   Dispatched,   // accepted and queued (fire-and-forget) -> 200
diff --git a/docs/local_http_api.md b/docs/local_http_api.md
index c6cef85..f785af0 100644
--- a/docs/local_http_api.md
+++ b/docs/local_http_api.md
@@ -50,6 +50,7 @@ curl "$AG_URL/api/v1/config"
 | `PUT` | `/api/v1/config` | `202` | Submit a partial configuration update. |
 | `POST` | `/api/v1/actions/calibrate-co2` | `200` | Request CO2 calibration when supported. |
 | `POST` | `/api/v1/actions/test-leds` | `200` | Request an LED diagnostic when supported. |
+| `POST` | `/api/v1/actions/test-gps` | `200` | Open the live GPS test when supported. |
 
 An endpoint can be absent when the product does not expose that capability. In
 that case, the HTTP server returns its normal `404` response. A registered
@@ -226,6 +227,7 @@ The v1 action catalog contains these actions:
 |---|---|---|---|
 | CO2 calibration | `POST /api/v1/actions/calibrate-co2` | None | Request CO2 calibration. |
 | LED test | `POST /api/v1/actions/test-leds` | None | Request the device LED diagnostic. |
+| GPS test | `POST /api/v1/actions/test-gps` | None | Open the device live GPS test. |
 
 An action may be unavailable for a product, current device state, or device
 policy. Unsupported actions return `404 not_found`; rejected actions return
@@ -284,6 +286,7 @@ activated; its mDNS advertisement follows Wi-Fi address availability.
 | `PUT` | `/api/v1/config` | When local configuration writes are allowed | Submit supported Go configuration changes. |
 | `POST` | `/api/v1/actions/calibrate-co2` | When actions are allowed | Request CO2 calibration. |
 | `POST` | `/api/v1/actions/test-leds` | When actions are allowed | Request the LED diagnostic. |
+| `POST` | `/api/v1/actions/test-gps` | When actions are allowed | Open the live GPS test. |
 
 ### Measures Fields
 
@@ -320,6 +323,7 @@ Go returns these fields from `GET /api/v1/config` and accepts them in partial
 |---|---|---|
 | CO2 calibration | `POST /api/v1/actions/calibrate-co2` | Available when actions are allowed. |
 | LED test | `POST /api/v1/actions/test-leds` | Available when actions are allowed. |
+| GPS test | `POST /api/v1/actions/test-gps` | Available when actions are allowed. |
 
 `configurationControl` determines whether local configuration writes, cloud
 configuration Fetch, or both are permitted. `cloudConnection` controls cloud
diff --git a/products/go/ARCHITECTURE.md b/products/go/ARCHITECTURE.md
index cd39ec5..8539ddf 100644
--- a/products/go/ARCHITECTURE.md
+++ b/products/go/ARCHITECTURE.md
@@ -878,8 +878,9 @@ Settings fields:
 - Returns a busy response if either the local FIFO or central event queue cannot
   admit a request; clearing the FIFO advances its epoch so stale events cannot
   consume requests from a later endpoint generation
-- Dispatches `calibrate-co2` and `test-leds` as fire-and-forget actions. The
-  HTTP success response confirms queue admission, not action completion
+- Dispatches `calibrate-co2`, `test-leds`, and `test-gps` as fire-and-forget
+  actions. The HTTP success response confirms queue admission, not action
+  completion
 - Uses plain HTTP without API authentication or TLS. The security boundary is a
   trusted local network, not exposure through an untrusted or public network
 - Retains routes and the listener across transient STA reconnects, restarts mDNS
diff --git a/products/go/docs/hardware_test.md b/products/go/docs/hardware_test.md
index 56b5e79..7b59ecb 100644
--- a/products/go/docs/hardware_test.md
+++ b/products/go/docs/hardware_test.md
@@ -111,11 +111,12 @@ LED marks the fix. The screen shows TTFF (`mm:ss`), fix type, satellites, HDOP,
 latitude/longitude, and UTC. On exit the posting cadence and back LED are
 restored, and the receiver is stopped only if the test ungated it.
 
-A cloud Fetch response can set `gpsTestRequested: true` to open this screen
-without manual Settings navigation. The orchestrator handles it after the CO2
-calibration and LED-test action flags from the same response. It ignores the
-request while the Peripheral or Accelerometer test is active and treats it as a
-no-op when the GPS Test screen is already open.
+A cloud Fetch response can set `gpsTestRequested: true`, or a Local API client
+can call `POST /api/v1/actions/test-gps`, to open this screen without manual
+Settings navigation. The orchestrator handles the cloud trigger after the CO2
+calibration and LED-test action flags from the same response. Both trigger paths
+ignore the request while the Peripheral or Accelerometer test is active and
+treat it as a no-op when the GPS Test screen is already open.
 
 See [`gps_service.md`](gps_service.md) for the receiver lifecycle.
 
diff --git a/products/go/docs/local_server.md b/products/go/docs/local_server.md
index 95c4a46..b3d6c8e 100644
--- a/products/go/docs/local_server.md
+++ b/products/go/docs/local_server.md
@@ -86,6 +86,7 @@ The Go integration registers exactly these routes:
 | `PUT` | `/api/v1/config` | Empty `202` | `400`, `403`, `404`, `503`, `500` |
 | `POST` | `/api/v1/actions/calibrate-co2` | Empty `200` | `403`, `503` |
 | `POST` | `/api/v1/actions/test-leds` | Empty `200` | `403`, `503` |
+| `POST` | `/api/v1/actions/test-gps` | Empty `200` | `403`, `503` |
 
 Errors produced by these handlers use an `application/json` envelope with
 `error.code`, optional `error.field`, and `error.message`:
@@ -227,6 +228,12 @@ the configured levels and current AQI state. The success response confirms only
 queue admission. If an interactive hardware-test screen owns the LEDs when the
 request is consumed, the diagnostic is ignored.
 
+`POST /api/v1/actions/test-gps` also returns empty `200` once queued. The
+orchestrator opens the live GPS Test screen and starts its existing receiver,
+fast-posting, and TTFF behavior. The request is ignored while the Peripheral or
+Accelerometer test is active and is a no-op when the GPS Test screen is already
+open.
+
 ### Endpoint Lifecycle
 
 ```mermaid
diff --git a/products/go/feature_overview.md b/products/go/feature_overview.md
index 08bc5cd..624334f 100644
--- a/products/go/feature_overview.md
+++ b/products/go/feature_overview.md
@@ -176,9 +176,10 @@ Configuration writes are asynchronous. For an update carrying at least one
 actual setting field, an accepted response means the request entered the device
 queue. Effect-free partials such as `{}` or `{"corrections":{}}` are immediate
 no-ops. A client reads the config endpoint to confirm that a requested value was
-persisted and became active. A local CO2 calibration request is also
-fire-and-forget: its response confirms queue admission, not dispatch to the
-sensor, calibration start, or completion.
+persisted and became active. Local actions can request CO2 calibration, the LED
+diagnostic, or direct navigation to the live GPS Test screen. They are
+fire-and-forget: a response confirms queue admission, not action dispatch or
+completion.
 
 The local API uses plain HTTP without API authentication or TLS. It is designed
 for a trusted private LAN and should not be exposed directly to an untrusted or
diff --git a/products/go/main/go_local_api.cpp b/products/go/main/go_local_api.cpp
index 04ca4d6..96bef29 100644
--- a/products/go/main/go_local_api.cpp
+++ b/products/go/main/go_local_api.cpp
@@ -200,7 +200,8 @@ ActionResult GoLocalApiService::trigger(ActionId action) {
     return {ActionStatus::Rejected};
   }
 
-  if (action != ActionId::CalibrateCo2 && action != ActionId::TestLeds) {
+  if (action != ActionId::CalibrateCo2 && action != ActionId::TestLeds &&
+      action != ActionId::TestGps) {
     _mutex.unlock();
     return {ActionStatus::NotSupported};
   }
diff --git a/products/go/main/go_orchestrator.cpp b/products/go/main/go_orchestrator.cpp
index 0f2ac28..fa879d7 100644
--- a/products/go/main/go_orchestrator.cpp
+++ b/products/go/main/go_orchestrator.cpp
@@ -771,13 +771,7 @@ void Orchestrator::handle_cloud_action_requests(const FetchConfigEventPayload &p
     run_led_test();
   }
   if (payload.gps_test_requested) {
-    const Screen current_screen = _svc.ui_manager.current_screen();
-    if (current_screen == Screen::PeripheralTest || current_screen == Screen::AccelTest) {
-      AG_LOGW(TAG, "GPS test trigger ignored: another hardware test is active");
-    } else if (current_screen != Screen::GpsTest) {
-      _svc.ui_manager.set_screen(Screen::GpsTest);
-      start_gps_test();
-    }
+    trigger_gps_test();
   }
 }
 
@@ -799,6 +793,9 @@ void Orchestrator::on_local_api_request(uint32_t event_epoch) {
     case ActionId::TestLeds:
       run_led_test();
       break;
+    case ActionId::TestGps:
+      trigger_gps_test();
+      break;
     default:
       AG_LOGW(TAG, "unsupported queued local action=%u", static_cast<unsigned>(request.action));
       break;
@@ -1572,6 +1569,20 @@ void Orchestrator::start_gps_test() {
   update_display();
 }
 
+void Orchestrator::trigger_gps_test() {
+  const Screen current_screen = _svc.ui_manager.current_screen();
+  if (current_screen == Screen::PeripheralTest || current_screen == Screen::AccelTest) {
+    AG_LOGW(TAG, "GPS test trigger ignored: another hardware test is active");
+    return;
+  }
+  if (current_screen == Screen::GpsTest) {
+    return;
+  }
+
+  _svc.ui_manager.set_screen(Screen::GpsTest);
+  start_gps_test();
+}
+
 void Orchestrator::finish_gps_test() {
   AG_LOGI(TAG, "gps test: finish");
   _svc.gps_service.set_posting_interval_ms(GPS_POSTING_INTERVAL_MS_DEFAULT);
diff --git a/products/go/main/go_orchestrator.h b/products/go/main/go_orchestrator.h
index 082e9d5..b2b6522 100644
--- a/products/go/main/go_orchestrator.h
+++ b/products/go/main/go_orchestrator.h
@@ -412,6 +412,9 @@ class Orchestrator {
   /// Enter the live GPS test: reset the TTFF timer, ungate the receiver if
   /// settings leave GPS inactive, speed up posting for a ~1 Hz refresh, render.
   void start_gps_test();
+  /// Open and start the GPS test unless it is already open or another live
+  /// hardware test owns the UI.
+  void trigger_gps_test();
   /// Leave the GPS test: restore the settings posting cadence and reconcile the
   /// receiver against settings (stop it if the test ungated it).
   void finish_gps_test();
diff --git a/products/go/tests/go_local_api.tests.cpp b/products/go/tests/go_local_api.tests.cpp
index 90afdaa..dcf945e 100644
--- a/products/go/tests/go_local_api.tests.cpp
+++ b/products/go/tests/go_local_api.tests.cpp
@@ -1063,14 +1063,17 @@ TEST_CASE("Go local API access changes do not implicitly clear admitted work") {
 TEST_CASE("Go local API action access precedes admission") {
   Fixture fixture;
   CHECK(fixture.service->trigger(ActionId::TestLeds).status == ActionStatus::Rejected);
+  CHECK(fixture.service->trigger(ActionId::TestGps).status == ActionStatus::Rejected);
   CHECK(fixture.service->trigger(ActionId::CalibrateCo2).status == ActionStatus::Rejected);
 
   fixture.service->set_access(ConfigAccess::ReadOnly);
   CHECK(fixture.service->trigger(ActionId::TestLeds).status == ActionStatus::Rejected);
+  CHECK(fixture.service->trigger(ActionId::TestGps).status == ActionStatus::Rejected);
   CHECK(fixture.service->trigger(ActionId::CalibrateCo2).status == ActionStatus::Rejected);
 
   fixture.service->set_access(ConfigAccess::ReadWrite);
   CHECK(fixture.service->trigger(ActionId::TestLeds).status == ActionStatus::Dispatched);
+  CHECK(fixture.service->trigger(ActionId::TestGps).status == ActionStatus::Dispatched);
   CHECK(fixture.service->trigger(ActionId::CalibrateCo2).status == ActionStatus::Dispatched);
 }
 
@@ -1080,7 +1083,8 @@ TEST_CASE("Go local API queues supported actions independently") {
 
   CHECK(fixture.service->trigger(ActionId::CalibrateCo2).status == ActionStatus::Dispatched);
   CHECK(fixture.service->trigger(ActionId::TestLeds).status == ActionStatus::Dispatched);
-  CHECK(GoLocalApiServiceTestAccess::request_count(*fixture.service) == 2);
+  CHECK(fixture.service->trigger(ActionId::TestGps).status == ActionStatus::Dispatched);
+  CHECK(GoLocalApiServiceTestAccess::request_count(*fixture.service) == 3);
 
   const LocalApiRequest calibration = fixture.receive_request();
   CHECK(calibration.kind == LocalApiRequestKind::Action);
@@ -1089,6 +1093,10 @@ TEST_CASE("Go local API queues supported actions independently") {
   const LocalApiRequest led_test = fixture.receive_request();
   CHECK(led_test.kind == LocalApiRequestKind::Action);
   CHECK(led_test.action == ActionId::TestLeds);
+
+  const LocalApiRequest gps_test = fixture.receive_request();
+  CHECK(gps_test.kind == LocalApiRequestKind::Action);
+  CHECK(gps_test.action == ActionId::TestGps);
 }
 
 TEST_CASE("Go local API rolls back action after admission failure") {
diff --git a/products/go/tests/go_orchestrator.tests.cpp b/products/go/tests/go_orchestrator.tests.cpp
index b8b3596..f83b8cf 100644
--- a/products/go/tests/go_orchestrator.tests.cpp
+++ b/products/go/tests/go_orchestrator.tests.cpp
@@ -7247,6 +7247,20 @@ TEST_CASE("local LED test action is queued and dispatched fire-and-forget",
   CHECK(test_spy::led_touch_all_on_seen);
 }
 
+TEST_CASE("local GPS test action opens the live test screen",
+          "[Orchestrator][local-api][action][gps-test]") {
+  TestFixture f;
+  auto orch = f.make_orchestrator();
+  f.local_api.set_access(ConfigAccess::ReadWrite);
+  REQUIRE(f.local_api.trigger(ActionId::TestGps).status == ActionStatus::Dispatched);
+
+  dispatch_next_local_request(f, orch);
+
+  CHECK(f.ui_manager.current_screen() == Screen::GpsTest);
+  CHECK(test_spy::gps_started);
+  CHECK(test_spy::gps_posting_interval_ms == 1000);
+}
+
 TEST_CASE("local settings remain unchanged until persistence commits",
           "[Orchestrator][local-api][config][ordering]") {
   TestFixture f;
diff --git a/products/go/tests/go_wifi.tests.cpp b/products/go/tests/go_wifi.tests.cpp
index 5ee011a..75f3d8a 100644
--- a/products/go/tests/go_wifi.tests.cpp
+++ b/products/go/tests/go_wifi.tests.cpp
@@ -32,6 +32,8 @@
 
 namespace {
 
+constexpr int LOCAL_API_ROUTE_COUNT = 6;
+
 // ---------------------------------------------------------------------------
 // FakeWifiHal — minimal in-memory HAL for WifiManager
 // ---------------------------------------------------------------------------
@@ -929,12 +931,12 @@ TEST_CASE("local endpoint starts routes before listener and advertises exact ide
   f.hal.got_ip_cb(0x0100A8C0);
 
   REQUIRE(f.svc.ensure_local_http());
-  CHECK(f.http.register_calls == 5);
+  CHECK(f.http.register_calls == LOCAL_API_ROUTE_COUNT);
   CHECK(f.http.start_calls == 1);
   CHECK(f.http.last_port == 8080);
   CHECK(WifiServiceTestAccess::local_http_active(f.svc));
   CHECK(f.svc.ensure_local_http());
-  CHECK(f.http.register_calls == 5);
+  CHECK(f.http.register_calls == LOCAL_API_ROUTE_COUNT);
   CHECK(f.http.start_calls == 1);
 
   REQUIRE(f.svc.ensure_local_mdns());
@@ -972,8 +974,8 @@ TEST_CASE("listener start failure rolls back local routes", "[go_wifi][local_end
 
   CHECK_FALSE(f.svc.ensure_local_http());
   CHECK_FALSE(WifiServiceTestAccess::local_http_active(f.svc));
-  CHECK(f.http.register_calls == 5);
-  CHECK(f.http.unregister_calls == 5);
+  CHECK(f.http.register_calls == LOCAL_API_ROUTE_COUNT);
+  CHECK(f.http.unregister_calls == LOCAL_API_ROUTE_COUNT);
   CHECK(f.hal.start_mdns_calls == 0);
 }
 
@@ -1050,7 +1052,7 @@ TEST_CASE("provisioning success handoff retains listener for local routes",
   CHECK(f.http.active_routes == 0);
   CHECK(f.svc.ensure_local_http());
   CHECK(f.http.start_calls == 2);
-  CHECK(f.http.active_routes == 5);
+  CHECK(f.http.active_routes == LOCAL_API_ROUTE_COUNT);
   CHECK(WifiServiceTestAccess::local_http_active(f.svc));
 }
 
@@ -1070,7 +1072,7 @@ TEST_CASE("local endpoint survives STA reconnect without route or listener churn
   f.hal.got_ip_cb(0x0100A8C0);
   REQUIRE(f.svc.ensure_local_http());
   REQUIRE(f.svc.ensure_local_mdns());
-  REQUIRE(f.http.active_routes == 5);
+  REQUIRE(f.http.active_routes == LOCAL_API_ROUTE_COUNT);
   REQUIRE(f.hal.start_mdns_calls == 1);
 
   REQUIRE(f.hal.sta_disconnected_cb);
@@ -1078,7 +1080,7 @@ TEST_CASE("local endpoint survives STA reconnect without route or listener churn
   CHECK(f.hal.stop_mdns_calls == 1);
   CHECK(f.http.stop_calls == 0);
   CHECK(f.http.unregister_calls == 0);
-  CHECK(f.http.active_routes == 5);
+  CHECK(f.http.active_routes == LOCAL_API_ROUTE_COUNT);
 
   f.hal.sta_connected_cb();
   f.hal.got_ip_cb(0x0200A8C0);
@@ -1086,8 +1088,8 @@ TEST_CASE("local endpoint survives STA reconnect without route or listener churn
   CHECK(f.svc.ensure_local_http());
   CHECK(f.svc.ensure_local_mdns());
   CHECK(f.http.start_calls == 1);
-  CHECK(f.http.register_calls == 5);
-  CHECK(f.http.active_routes == 5);
+  CHECK(f.http.register_calls == LOCAL_API_ROUTE_COUNT);
+  CHECK(f.http.active_routes == LOCAL_API_ROUTE_COUNT);
 }
 
 TEST_CASE("shutdown stops a listener retained by Wi-Fi to BLE provisioning switch",
diff --git a/products/go/tests/local-server-integration/README.md b/products/go/tests/local-server-integration/README.md
index 46bdaf9..f698b8f 100644
--- a/products/go/tests/local-server-integration/README.md
+++ b/products/go/tests/local-server-integration/README.md
@@ -69,7 +69,9 @@ pytest products/go/tests/local-server-integration/ -v \
 ## Safety
 
 The default suite does not change durable configuration. It submits only an
-empty configuration update, malformed requests, and the unsupported LED action.
+empty configuration update, malformed requests, and the LED and GPS test
+actions. The GPS action leaves the live GPS Test screen open for the operator to
+exit.
 
 Persisted mutation tests require `--ago-allow-config-write`. They round-trip the
 temperature unit, measurement and GPS settings, three LED levels, buzzer, CO2
@@ -122,8 +124,9 @@ and known fields unsupported by Go.
 
 ### `test_actions.py` — Actions
 
-Verifies that `test-leds` returns an empty `200` fire-and-forget response. The
-opt-in calibration test verifies the same response contract for `calibrate-co2`.
+Verifies that `test-leds` and `test-gps` return empty `200` fire-and-forget
+responses. The opt-in calibration test verifies the same response contract for
+`calibrate-co2`.
 
 ### `test_ota.py` — OTA Policy
 
diff --git a/products/go/tests/local-server-integration/ago_local_api.py b/products/go/tests/local-server-integration/ago_local_api.py
index 37c2b79..2977c0f 100644
--- a/products/go/tests/local-server-integration/ago_local_api.py
+++ b/products/go/tests/local-server-integration/ago_local_api.py
@@ -14,6 +14,7 @@
 CONFIG_PATH = "/api/v1/config"
 CALIBRATE_CO2_PATH = "/api/v1/actions/calibrate-co2"
 TEST_LEDS_PATH = "/api/v1/actions/test-leds"
+TEST_GPS_PATH = "/api/v1/actions/test-gps"
 
 MODEL = "P-1PSG"
 SERVICE_TYPE = "_airgradient._tcp.local."
diff --git a/products/go/tests/local-server-integration/test_actions.py b/products/go/tests/local-server-integration/test_actions.py
index 0470331..6716559 100644
--- a/products/go/tests/local-server-integration/test_actions.py
+++ b/products/go/tests/local-server-integration/test_actions.py
@@ -12,6 +12,10 @@ def test_led_action_is_dispatched(ago_http_client: httpx.Client) -> None:
     api.assert_empty_response(ago_http_client.post(api.TEST_LEDS_PATH), 200)
 
 
+def test_gps_action_is_dispatched(ago_http_client: httpx.Client) -> None:
+    api.assert_empty_response(ago_http_client.post(api.TEST_GPS_PATH), 200)
+
+
 @pytest.mark.interactive
 def test_calibrate_co2_is_dispatched(
     ago_http_client: httpx.Client,
diff --git a/products/go/tests/local-server-integration/test_ota.py b/products/go/tests/local-server-integration/test_ota.py
index f8a98ed..341f7ba 100644
--- a/products/go/tests/local-server-integration/test_ota.py
+++ b/products/go/tests/local-server-integration/test_ota.py
@@ -60,6 +60,19 @@ def test_led_action_is_forbidden(
     )
 
 
+def test_gps_action_is_forbidden(
+    ago_http_client: httpx.Client,
+    require_ota_active: None,
+) -> None:
+    del require_ota_active
+    api.assert_error(
+        ago_http_client.post(api.TEST_GPS_PATH),
+        403,
+        "forbidden",
+        "forbidden",
+    )
+
+
 @pytest.mark.interactive
 def test_calibration_action_is_forbidden(
     ago_http_client: httpx.Client,
diff --git a/products/reference/main/test_local_server.cpp b/products/reference/main/test_local_server.cpp
index e7f90a0..72a8dbe 100644
--- a/products/reference/main/test_local_server.cpp
+++ b/products/reference/main/test_local_server.cpp
@@ -355,6 +355,9 @@ class DemoActionHandler : public ActionHandler {
     case ActionId::TestLeds:
       ESP_LOGI(TAG, "action: test-leds dispatched");
       break;
+    case ActionId::TestGps:
+      ESP_LOGI(TAG, "action: test-gps dispatched");
+      break;
     }
     return {ActionStatus::Dispatched};
   }
diff --git a/products/reference/main/test_local_server.h b/products/reference/main/test_local_server.h
index e1e0ce6..6aff5ff 100644
--- a/products/reference/main/test_local_server.h
+++ b/products/reference/main/test_local_server.h
@@ -18,6 +18,7 @@
 //   PUT  http://<device-ip>/api/v1/config            (partial JSON -> 202)
 //   POST http://<device-ip>/api/v1/actions/calibrate-co2  (-> 200)
 //   POST http://<device-ip>/api/v1/actions/test-leds      (-> 200)
+//   POST http://<device-ip>/api/v1/actions/test-gps       (-> 200)
 //
 // A 202 confirms admission, not completion. Poll GET /api/v1/config for
 // convergence; retry a structured 503 busy response using client-owned timing.

From b1df7f754d5945f8b3ed23dfe63fb4c9d1dbe32a Mon Sep 17 00:00:00 2001
From: samuelbles07 <samuelbles07@gmail.com>
Date: Fri, 7 Aug 2026 12:44:20 +0700
Subject: [PATCH 3/3] fix(go): ignore custom PM EPA flag

Go custom PM corrections no longer emit or apply useEpa2021. Cloud, Local API, and legacy BLE values are ignored.
---
 products/go/docs/ble_service.md               | 15 +++--
 products/go/docs/cloud_service.md             |  2 +-
 products/go/docs/local_server.md              |  3 +-
 products/go/docs/measurement_corrections.md   | 23 ++++---
 products/go/docs/settings.md                  |  5 +-
 products/go/go_ble_client.md                  |  6 +-
 products/go/main/go_ble.cpp                   | 11 +---
 products/go/main/go_ble_protocol.h            |  3 +-
 products/go/main/go_cloud.cpp                 |  5 +-
 products/go/main/go_local_api.cpp             |  5 +-
 products/go/main/go_settings.cpp              | 11 +---
 .../go/tests/ble-integration/test_config.py   | 10 +---
 products/go/tests/go_ble.tests.cpp            | 60 ++++++++++++++++++-
 products/go/tests/go_cloud.tests.cpp          | 23 ++++++-
 products/go/tests/go_local_api.tests.cpp      | 33 +++++-----
 products/go/tests/go_settings.tests.cpp       | 10 +++-
 .../local-server-integration/ago_local_api.py |  4 --
 17 files changed, 141 insertions(+), 88 deletions(-)

diff --git a/products/go/docs/ble_service.md b/products/go/docs/ble_service.md
index 0195354..b1fc0e7 100644
--- a/products/go/docs/ble_service.md
+++ b/products/go/docs/ble_service.md
@@ -405,14 +405,13 @@ keeps this value updated whenever the orchestrator calls `update_config()`.
 Each correction map contains schema version `"s"` and a positional `"v"` array.
 Schema version 1 uses `[algorithm, scale, intercept]` for temperature and
 humidity, and `[algorithm, scale, intercept, flags]` for PM2.5. Coefficients are
-finite float32 values. The PM2.5 flags value uses bit 0 for `use_epa`; the flag
-must be clear unless the algorithm is `custom_via_pm25_raw`. The canonical
-`none` representation uses identity coefficients, but the encoder emits active
-coefficients verbatim. The decoder requires finite coefficients but does not
-enforce identity values for `none`; nonidentity values are ignored by correction
-math, remain visible until persisted settings are reloaded, and are canonicalized
-on reload. The full snapshot includes all array values so clients can render and
-round-trip the current state.
+finite float32 values. Go reserves PM2.5 flag bit 0 for wire compatibility: the
+encoder always clears it and the decoder accepts but ignores it for
+`custom_via_pm25_raw`. The canonical `none` representation uses identity
+coefficients, but the encoder emits active coefficients verbatim. The decoder
+requires finite coefficients but does not enforce identity values for `none`;
+nonidentity values are ignored by correction math, remain visible until
+persisted settings are reloaded, and are canonicalized on reload.
 
 | Algorithm | PM2.5 | Temperature / Humidity |
 |---|---|---|
diff --git a/products/go/docs/cloud_service.md b/products/go/docs/cloud_service.md
index f41cdd6..6646484 100644
--- a/products/go/docs/cloud_service.md
+++ b/products/go/docs/cloud_service.md
@@ -186,7 +186,7 @@ Sensor and correction fields are:
 Each valid scalar or correction sets its own update-mask bit. A malformed field
 does not prevent valid siblings from being delivered. Missing fields retain the
 active setting, and custom coefficients must be finite JSON numbers with exact
-property names.
+property names. Go ignores `useEpa2021` in custom PM2.5 corrections.
 
 Cloud FETCH does not own connectivity or writer authority. The parser ignores
 `cloudConnection`/`disableCloudConnection` and `configurationControl`, and the
diff --git a/products/go/docs/local_server.md b/products/go/docs/local_server.md
index b3d6c8e..3283b54 100644
--- a/products/go/docs/local_server.md
+++ b/products/go/docs/local_server.md
@@ -165,7 +165,8 @@ Connectivity, sensor, and correction fields are:
 
 Go accepts `none`, `epa_2021`, and `custom_via_pm25_raw` for PM2.5. Temperature
 and humidity accept `none` and `custom`. Custom entries require finite
-`intercept` and `scalingFactor` values; PM2.5 also requires `useEpa2021`.
+`intercept` and `scalingFactor` values. Go omits the shared `useEpa2021` field
+from GET responses and ignores it when supplied in a PM2.5 PUT.
 Partial correction objects preserve omitted active siblings. Other known v1
 catalog fields are omitted from GET and return `404 not_found` on PUT when
 endpoint and source policy otherwise permit the request.
diff --git a/products/go/docs/measurement_corrections.md b/products/go/docs/measurement_corrections.md
index b95c0f3..b0c9cdf 100644
--- a/products/go/docs/measurement_corrections.md
+++ b/products/go/docs/measurement_corrections.md
@@ -59,17 +59,15 @@ Algorithm and property names are case-sensitive.
 |---|---|---|
 | PM2.5 | `none` | Preserve valid raw PM2.5 |
 | PM2.5 | `epa_2021` | Apply the EPA 2021 piecewise correction using raw averaged PM2.5 and raw averaged humidity |
-| PM2.5 | `custom_via_pm25_raw` | Apply a linear scale and intercept to raw PM2.5, then optionally apply EPA 2021 using raw humidity |
+| PM2.5 | `custom_via_pm25_raw` | Apply a linear scale and intercept to raw PM2.5 |
 | Temperature | `none` | Preserve valid raw temperature |
 | Temperature | `custom` | Apply `scaling factor * raw + intercept` in Celsius |
 | Humidity | `none` | Preserve valid raw relative humidity |
 | Humidity | `custom` | Apply `scaling factor * raw + intercept` |
 
 The PM custom transform preserves an exact raw zero instead of adding the
-intercept and clamps negative finite results to zero. Its optional EPA stage
-runs after the linear stage but still uses raw, not humidity-corrected,
-humidity. Temperature conversion to Fahrenheit and all presentation rounding
-happen after correction.
+intercept and clamps negative finite results to zero. Temperature conversion to
+Fahrenheit and all presentation rounding happen after correction.
 
 For the EPA transform, let `p` be PM2.5 and `h` be raw relative humidity clamped
 to its valid range. The implemented piecewise equations are:
@@ -97,9 +95,8 @@ p >= 260:
 
 The final finite result is floored at zero. The source of truth remains
 [`measurement_corrections.cpp`](../../../components/airgradient-common/measurement_corrections.cpp).
-Tests exercise the boundary inputs and cover PM custom zero, ordering, and
-invalid-humidity fallback; exact expected EPA values are not asserted at every
-boundary.
+Tests exercise the boundary inputs and PM custom zero behavior; exact expected
+EPA values are not asserted at every boundary.
 
 ### Wire Names and Shapes
 
@@ -113,7 +110,7 @@ use different measure and PM scaling-factor names.
 | Humidity entry | `corrections.humidity` | `corrections.rhum` |
 | PM custom scaling factor | `slr.scalingFactor` | `slr.scalingFactorViaPm25` |
 | Linear custom scaling factor | `slr.scalingFactor` | `slr.scalingFactor` |
-| Shared fields | `correctionAlgorithm`, `slr.intercept`, `slr.useEpa2021` | `correctionAlgorithm`, `slr.intercept`, `slr.useEpa2021` |
+| Shared fields | `correctionAlgorithm`, `slr.intercept` | `correctionAlgorithm`, `slr.intercept` |
 
 Local Config parsing is strict. Correction objects accept only `pm25`,
 `temperature`, and `humidity`; each entry accepts only `correctionAlgorithm`
@@ -126,7 +123,8 @@ Local API algorithm shapes are:
   as null.
 - PM2.5 `epa_2021` has the same no-SLR shape.
 - PM2.5 `custom_via_pm25_raw` requires finite, float-representable
-  `intercept` and `scalingFactor` numbers plus Boolean `useEpa2021` in `slr`.
+  `intercept` and `scalingFactor` numbers. The shared Local API schema accepts
+  `useEpa2021`, but Go ignores it and omits it from GET responses.
 - Temperature and humidity `custom` require finite, float-representable
   `intercept` and `scalingFactor` numbers in `slr`; `useEpa2021` is rejected.
 
@@ -134,8 +132,9 @@ The cloud parser tolerates unrelated root, correction-entry, and SLR fields,
 but the supported values retain strict types and required names. Cloud PM2.5
 custom input requires `scalingFactorViaPm25`; `scalingFactor` is not an alias.
 Cloud custom inputs require all parameters, while `none` and `epa_2021` ignore
-`slr`. A malformed cloud measure leaves only that measure's update bit clear,
-so valid siblings remain applicable.
+`slr`. Go ignores `useEpa2021` when it is present. A malformed cloud measure
+leaves only that measure's update bit clear, so valid siblings remain
+applicable.
 
 See the local component
 [`config_json.tests.cpp`](../../../components/airgradient-local-server/tests/config_json.tests.cpp),
diff --git a/products/go/docs/settings.md b/products/go/docs/settings.md
index 7399960..79975b9 100644
--- a/products/go/docs/settings.md
+++ b/products/go/docs/settings.md
@@ -67,7 +67,7 @@ IEEE-754 blob accessors.
 
 | Measure | Supported algorithms | Required custom values |
 |---|---|---|
-| PM2.5 | `none`, `epa_2021`, `custom_via_pm25_raw` | `intercept`, `scalingFactorViaPm25`, `useEpa2021` |
+| PM2.5 | `none`, `epa_2021`, `custom_via_pm25_raw` | `intercept`, `scalingFactorViaPm25` |
 | Temperature | `none`, `custom` | `intercept`, `scalingFactor` |
 | Humidity | `none`, `custom` | `intercept`, `scalingFactor` |
 
@@ -75,7 +75,8 @@ Missing or invalid algorithms fall back to `none`. A custom correction is
 active only when every required coefficient is present and finite. PM2.5
 `none` and `epa_2021` do not require persisted coefficients and load with
 identity parameters. Factory reset writes the default all-`none` correction
-set.
+set. Go ignores the retired `useEpa2021` custom-PM option and does not read or
+write its former `mc_pe` NVS key.
 
 Wi-Fi SSID and password are owned by `WifiManager`'s saved-networks store
 (its own `wifi_creds` NVS namespace, injected at construction). Only the
diff --git a/products/go/go_ble_client.md b/products/go/go_ble_client.md
index 860a471..6837179 100644
--- a/products/go/go_ble_client.md
+++ b/products/go/go_ble_client.md
@@ -538,8 +538,8 @@ Schema version 1 uses `[algorithm, scale, intercept]` for temperature and
 humidity, and `[algorithm, scale, intercept, flags]` for PM2.5. All coefficients
 are finite float32 values. Algorithm enums are `0 = none`, `1 = custom` for
 temperature/humidity, and `0 = none`, `1 = epa_2021`, `2 = custom_via_pm25_raw`
-for PM2.5. PM2.5 flag bit 0 is `use_epa`.
-The flag must be clear unless the PM2.5 algorithm is `custom_via_pm25_raw`.
+for PM2.5. PM2.5 flag bit 0 is reserved for compatibility. Go always emits it
+clear and ignores it on `custom_via_pm25_raw` writes.
 Canonical `none` uses scale `1.0`, intercept `0.0`, and clear flags. The current
 decoder accepts other finite coefficients for `none`; correction math ignores
 them and persisted loading canonicalizes them.
@@ -579,7 +579,7 @@ them and persisted loading canonicalizes them.
   "abc": 7,
   "tlo": 12,
   "nlo": 12,
-  "pm25_corr": {"s": 1, "v": [2, 1.08, -0.2, 1]},
+  "pm25_corr": {"s": 1, "v": [2, 1.08, -0.2, 0]},
   "temp_corr": {"s": 1, "v": [0, 1.0, 0.0]},
   "hum_corr": {"s": 1, "v": [0, 1.0, 0.0]}
 }
diff --git a/products/go/main/go_ble.cpp b/products/go/main/go_ble.cpp
index 86a7e02..fb6060c 100644
--- a/products/go/main/go_ble.cpp
+++ b/products/go/main/go_ble.cpp
@@ -190,9 +190,7 @@ void encode_pm25_correction(CborEncoder &map, const Pm25Correction &correction)
   cbor_encode_uint(&values, pm25_correction_algorithm_to_wire(correction.algorithm));
   cbor_encode_float(&values, correction.scaling_factor);
   cbor_encode_float(&values, correction.intercept);
-  const bool use_epa =
-      correction.algorithm == Pm25CorrectionAlgorithm::CustomViaPm25Raw && correction.use_epa2021;
-  cbor_encode_uint(&values, use_epa ? BLE_PM25_CORRECTION_FLAG_USE_EPA : 0);
+  cbor_encode_uint(&values, 0);
   cbor_encoder_close_container(&value, &values);
 
   cbor_encoder_close_container(&map, &value);
@@ -260,11 +258,9 @@ bool decode_pm25_values(CborValue &value, Pm25Correction &out, bool &invalid) {
 
   uint64_t flags = 0;
   if (cbor_value_at_end(&values) || !read_uint(values, flags) ||
-      (flags & ~BLE_PM25_CORRECTION_FLAG_USE_EPA) != 0 ||
+      (flags & ~BLE_PM25_CORRECTION_ALLOWED_RESERVED_FLAGS) != 0 ||
       (out.algorithm != Pm25CorrectionAlgorithm::CustomViaPm25Raw && flags != 0)) {
     invalid = true;
-  } else {
-    out.use_epa2021 = (flags & BLE_PM25_CORRECTION_FLAG_USE_EPA) != 0;
   }
   if (!cbor_value_at_end(&values)) {
     cbor_value_advance(&values);
@@ -1911,8 +1907,7 @@ static bool dif_nlo(const GoSettings &a, const GoSettings &b) {
 static bool dif_pm25_correction(const GoSettings &a, const GoSettings &b) {
   return a.corrections.pm25.algorithm != b.corrections.pm25.algorithm ||
          a.corrections.pm25.scaling_factor != b.corrections.pm25.scaling_factor ||
-         a.corrections.pm25.intercept != b.corrections.pm25.intercept ||
-         a.corrections.pm25.use_epa2021 != b.corrections.pm25.use_epa2021;
+         a.corrections.pm25.intercept != b.corrections.pm25.intercept;
 }
 static bool dif_temp_correction(const GoSettings &a, const GoSettings &b) {
   return a.corrections.temperature.algorithm != b.corrections.temperature.algorithm ||
diff --git a/products/go/main/go_ble_protocol.h b/products/go/main/go_ble_protocol.h
index 614321b..22a93d3 100644
--- a/products/go/main/go_ble_protocol.h
+++ b/products/go/main/go_ble_protocol.h
@@ -91,7 +91,8 @@ inline constexpr const char *BLE_KEY_CORRECTION_SCHEMA = "s";
 inline constexpr const char *BLE_KEY_CORRECTION_VALUES = "v";
 
 inline constexpr uint64_t BLE_CORRECTION_SCHEMA_VERSION = 1;
-inline constexpr uint64_t BLE_PM25_CORRECTION_FLAG_USE_EPA = 1U << 0;
+// Schema-v1 compatibility: bit 0 is accepted on writes but ignored by Go.
+inline constexpr uint64_t BLE_PM25_CORRECTION_ALLOWED_RESERVED_FLAGS = 1U << 0;
 
 // ---------------------------------------------------------------------------
 // Aiding command keys (payload fields for "set_aiding" command)
diff --git a/products/go/main/go_cloud.cpp b/products/go/main/go_cloud.cpp
index b9af958..cc637ba 100644
--- a/products/go/main/go_cloud.cpp
+++ b/products/go/main/go_cloud.cpp
@@ -70,7 +70,6 @@ constexpr const char *JSON_SLR = "slr";
 constexpr const char *JSON_INTERCEPT = "intercept";
 constexpr const char *JSON_SCALING_FACTOR = "scalingFactor";
 constexpr const char *JSON_SCALING_FACTOR_VIA_PM25 = "scalingFactorViaPm25";
-constexpr const char *JSON_USE_EPA2021 = "useEpa2021";
 
 uint32_t deadline_wait_ms(uint32_t now, uint32_t deadline) {
   return static_cast<int32_t>(now - deadline) >= 0 ? 0 : deadline - now;
@@ -268,13 +267,11 @@ bool parse_pm25_correction(const cJSON *entry, Pm25Correction &out) {
   parsed.algorithm = Pm25CorrectionAlgorithm::CustomViaPm25Raw;
   const cJSON *intercept = cJSON_GetObjectItemCaseSensitive(slr, JSON_INTERCEPT);
   const cJSON *scaling_factor = cJSON_GetObjectItemCaseSensitive(slr, JSON_SCALING_FACTOR_VIA_PM25);
-  const cJSON *use_epa2021 = cJSON_GetObjectItemCaseSensitive(slr, JSON_USE_EPA2021);
   if (!parse_float(intercept, parsed.intercept) ||
-      !parse_float(scaling_factor, parsed.scaling_factor) || !cJSON_IsBool(use_epa2021)) {
+      !parse_float(scaling_factor, parsed.scaling_factor)) {
     AG_LOGW(TAG, "correction %s rejected: custom parameters are invalid", JSON_PM25);
     return false;
   }
-  parsed.use_epa2021 = cJSON_IsTrue(use_epa2021) != 0;
 
   out = parsed;
   return true;
diff --git a/products/go/main/go_local_api.cpp b/products/go/main/go_local_api.cpp
index 96bef29..679aac9 100644
--- a/products/go/main/go_local_api.cpp
+++ b/products/go/main/go_local_api.cpp
@@ -74,7 +74,6 @@ CorrectionEntry make_pm25_correction(const Pm25Correction &correction) {
     SlrParams slr{};
     slr.intercept = correction.intercept;
     slr.scaling_factor = correction.scaling_factor;
-    slr.use_epa2021 = correction.use_epa2021;
     entry.slr = slr;
     break;
   }
@@ -689,8 +688,7 @@ bool GoLocalApiService::translate_pm25_correction(const CorrectionEntry &entry,
     return true;
   }
 
-  if (entry.algorithm != CORRECTION_CUSTOM_PM25 || !entry.slr.has_value() ||
-      !entry.slr->use_epa2021.has_value()) {
+  if (entry.algorithm != CORRECTION_CUSTOM_PM25 || !entry.slr.has_value()) {
     return false;
   }
 
@@ -700,7 +698,6 @@ bool GoLocalApiService::translate_pm25_correction(const CorrectionEntry &entry,
       !to_finite_float(entry.slr->scaling_factor, parsed.scaling_factor)) {
     return false;
   }
-  parsed.use_epa2021 = *entry.slr->use_epa2021;
   correction = parsed;
   return true;
 }
diff --git a/products/go/main/go_settings.cpp b/products/go/main/go_settings.cpp
index c6dbdbf..7ef7eed 100644
--- a/products/go/main/go_settings.cpp
+++ b/products/go/main/go_settings.cpp
@@ -38,7 +38,6 @@ constexpr const char *KEY_ONBOARDING_DONE = "obd";
 constexpr const char *KEY_PM25_CORRECTION_ALGORITHM = "mc_pa";
 constexpr const char *KEY_PM25_CORRECTION_SCALING_FACTOR = "mc_ps";
 constexpr const char *KEY_PM25_CORRECTION_INTERCEPT = "mc_pi";
-constexpr const char *KEY_PM25_CORRECTION_USE_EPA2021 = "mc_pe";
 constexpr const char *KEY_TEMP_CORRECTION_ALGORITHM = "mc_ta";
 constexpr const char *KEY_TEMP_CORRECTION_SCALING_FACTOR = "mc_ts";
 constexpr const char *KEY_TEMP_CORRECTION_INTERCEPT = "mc_ti";
@@ -100,14 +99,11 @@ MeasurementCorrections load_measurement_corrections(ConfigStore &store) {
     } else if (pm_algorithm == Pm25CorrectionAlgorithm::CustomViaPm25Raw) {
       float scaling_factor = 0.0f;
       float intercept = 0.0f;
-      bool use_epa2021 = false;
       if (load_finite_float(store, KEY_PM25_CORRECTION_SCALING_FACTOR, scaling_factor) &&
-          load_finite_float(store, KEY_PM25_CORRECTION_INTERCEPT, intercept) &&
-          store.get_bool(KEY_PM25_CORRECTION_USE_EPA2021, use_epa2021) == ConfigStoreResult::OK) {
+          load_finite_float(store, KEY_PM25_CORRECTION_INTERCEPT, intercept)) {
         corrections.pm25.algorithm = pm_algorithm;
         corrections.pm25.scaling_factor = scaling_factor;
         corrections.pm25.intercept = intercept;
-        corrections.pm25.use_epa2021 = use_epa2021;
       }
     }
   }
@@ -157,8 +153,6 @@ bool save_measurement_corrections(ConfigStore &store, const MeasurementCorrectio
       store.set_float(KEY_PM25_CORRECTION_SCALING_FACTOR, corrections.pm25.scaling_factor) !=
           ConfigStoreResult::OK ||
       store.set_float(KEY_PM25_CORRECTION_INTERCEPT, corrections.pm25.intercept) !=
-          ConfigStoreResult::OK ||
-      store.set_bool(KEY_PM25_CORRECTION_USE_EPA2021, corrections.pm25.use_epa2021) !=
           ConfigStoreResult::OK) {
     return false;
   }
@@ -595,13 +589,12 @@ void print_settings(const GoSettings &settings) {
           settings.tvoc_learning_offset, settings.nox_learning_offset,
           settings.static_ip.ip != 0 ? "set" : "dhcp", settings.onboarding_done ? "true" : "false");
   AG_LOGI(TAG,
-          "** corrections | pm_alg=%d pm_scale=%.6f pm_intercept=%.6f pm_epa=%s "
+          "** corrections | pm_alg=%d pm_scale=%.6f pm_intercept=%.6f "
           "temp_alg=%d temp_scale=%.6f temp_intercept=%.6f "
           "hum_alg=%d hum_scale=%.6f hum_intercept=%.6f **",
           static_cast<int>(settings.corrections.pm25.algorithm),
           static_cast<double>(settings.corrections.pm25.scaling_factor),
           static_cast<double>(settings.corrections.pm25.intercept),
-          settings.corrections.pm25.use_epa2021 ? "true" : "false",
           static_cast<int>(settings.corrections.temperature.algorithm),
           static_cast<double>(settings.corrections.temperature.scaling_factor),
           static_cast<double>(settings.corrections.temperature.intercept),
diff --git a/products/go/tests/ble-integration/test_config.py b/products/go/tests/ble-integration/test_config.py
index dbba45c..697b6e0 100644
--- a/products/go/tests/ble-integration/test_config.py
+++ b/products/go/tests/ble-integration/test_config.py
@@ -117,7 +117,7 @@ def test_correction_maps_valid(self, config_payload: dict):
             if key == "pm25_corr":
                 assert algorithm in proto.PM25_CORRECTION_ALGORITHMS.values()
                 assert type(values[3]) is int
-                assert values[3] & ~proto.PM25_CORRECTION_FLAG_USE_EPA == 0
+                assert values[3] == 0, "Config['pm25_corr'] reserved flags must be clear"
             else:
                 assert algorithm in proto.LINEAR_CORRECTION_ALGORITHMS.values()
             assert isinstance(values[1], float)
@@ -126,14 +126,6 @@ def test_correction_maps_valid(self, config_payload: dict):
             assert math.isfinite(values[1])
             assert math.isfinite(values[2])
 
-            if key == "pm25_corr" and values[0] not in {
-                proto.PM25_CORRECTION_ALGORITHMS["custom_via_pm25_raw"],
-            }:
-                assert values[3] == 0, (
-                    f"Config['{key}'] EPA flags must be clear for algorithm {values[0]}"
-                )
-
-
 # ---------------------------------------------------------------------------
 # Write tests — async, interactive BLE I/O per test
 # ---------------------------------------------------------------------------
diff --git a/products/go/tests/go_ble.tests.cpp b/products/go/tests/go_ble.tests.cpp
index 0c3a555..774be12 100644
--- a/products/go/tests/go_ble.tests.cpp
+++ b/products/go/tests/go_ble.tests.cpp
@@ -407,6 +407,49 @@ static bool top_level_value_is_map(const uint8_t *data, size_t len, const char *
   return false;
 }
 
+static uint64_t pm25_correction_flags(const uint8_t *data, size_t len) {
+  CborParser parser;
+  CborValue root;
+  REQUIRE(cbor_parser_init(data, len, 0, &parser, &root) == CborNoError);
+
+  CborValue map;
+  REQUIRE(cbor_value_enter_container(&root, &map) == CborNoError);
+  while (!cbor_value_at_end(&map)) {
+    size_t key_len = 0;
+    REQUIRE(cbor_value_get_string_length(&map, &key_len) == CborNoError);
+    std::string key(key_len, '\0');
+    REQUIRE(cbor_value_copy_text_string(&map, key.data(), &key_len, &map) == CborNoError);
+    if (key != "pm25_corr") {
+      REQUIRE(cbor_value_advance(&map) == CborNoError);
+      continue;
+    }
+
+    CborValue correction;
+    REQUIRE(cbor_value_enter_container(&map, &correction) == CborNoError);
+    while (!cbor_value_at_end(&correction)) {
+      REQUIRE(cbor_value_get_string_length(&correction, &key_len) == CborNoError);
+      key.assign(key_len, '\0');
+      REQUIRE(cbor_value_copy_text_string(&correction, key.data(), &key_len, &correction) ==
+              CborNoError);
+      if (key != "v") {
+        REQUIRE(cbor_value_advance(&correction) == CborNoError);
+        continue;
+      }
+
+      CborValue values;
+      REQUIRE(cbor_value_enter_container(&correction, &values) == CborNoError);
+      for (int i = 0; i < 3; ++i) {
+        REQUIRE(cbor_value_advance(&values) == CborNoError);
+      }
+      uint64_t flags = 0;
+      REQUIRE(cbor_value_get_uint64(&values, &flags) == CborNoError);
+      return flags;
+    }
+  }
+  FAIL("pm25_corr.v missing");
+  return UINT64_MAX;
+}
+
 // Conservative single-PDU budget (mirrors BLE_NOTIFY_MAX_BYTES in go_ble.cpp);
 // the 185-byte minimum MTU yields a 182-byte PDU, so 180 is the test bound.
 static constexpr size_t TEST_NOTIFY_BUDGET = 180;
@@ -862,6 +905,19 @@ TEST_CASE("BLE: encode_config values match settings") {
   CHECK(find_entry(entries, "nlo")->uint_val == LEARNING_OFFSET_HOURS_MAX);
 }
 
+TEST_CASE("BLE: encode_config clears the retired PM25 EPA flag") {
+  StorageService storage(*null_cache_ptr, *null_nand_ptr);
+  BleService svc(nullptr, storage, default_ble_server);
+  GoSettings settings{};
+  settings.corrections.pm25.algorithm = Pm25CorrectionAlgorithm::CustomViaPm25Raw;
+  settings.corrections.pm25.use_epa2021 = true;
+
+  uint8_t buf[512];
+  const size_t len = BleServiceTestAccess::encode_config(svc, buf, sizeof(buf), settings);
+  REQUIRE(len > 0);
+  CHECK(pm25_correction_flags(buf, len) == 0);
+}
+
 // ---------------------------------------------------------------------------
 // encode_config_delta (NOTIFY form: "type":"config" + changed fields only)
 // ---------------------------------------------------------------------------
@@ -1522,7 +1578,7 @@ TEST_CASE("BLE: decode_config_write rejects invalid requested config values") {
   CHECK(settings.nox_learning_offset == original.nox_learning_offset);
 }
 
-TEST_CASE("BLE: decode_config_write decodes PM25 correction group") {
+TEST_CASE("BLE: decode_config_write ignores the retired PM25 EPA flag") {
   uint8_t buf[192];
   size_t len = encode_set_pm25_correction(buf, sizeof(buf), 2, 1.08f, -0.2f, true);
 
@@ -1536,7 +1592,7 @@ TEST_CASE("BLE: decode_config_write decodes PM25 correction group") {
   CHECK(settings.corrections.pm25.algorithm == Pm25CorrectionAlgorithm::CustomViaPm25Raw);
   CHECK(settings.corrections.pm25.scaling_factor == Catch::Approx(1.08f));
   CHECK(settings.corrections.pm25.intercept == Catch::Approx(-0.2f));
-  CHECK(settings.corrections.pm25.use_epa2021);
+  CHECK_FALSE(settings.corrections.pm25.use_epa2021);
 }
 
 TEST_CASE("BLE: decode_config_write decodes linear correction group") {
diff --git a/products/go/tests/go_cloud.tests.cpp b/products/go/tests/go_cloud.tests.cpp
index 54ee818..d0d1d87 100644
--- a/products/go/tests/go_cloud.tests.cpp
+++ b/products/go/tests/go_cloud.tests.cpp
@@ -381,7 +381,7 @@ TEST_CASE("FETCH forwards AgClientResult into FetchConfigResult event", "[CloudS
 TEST_CASE("FETCH parses supported corrections independently", "[CloudService][fetch][correction]") {
   CloudFixture f;
   const char body[] =
-      R"({"country":"DE","corrections":{"pm02":{"correctionAlgorithm":"custom_via_pm25_raw","slr":{"intercept":0,"scalingFactorViaPm25":1.08,"useEpa2021":true}},"atmp":{"correctionAlgorithm":"custom","slr":{"intercept":-0.4,"scalingFactor":1}},"rhum":{"correctionAlgorithm":"none","slr":null}}})";
+      R"({"country":"DE","corrections":{"pm02":{"correctionAlgorithm":"custom_via_pm25_raw","slr":{"intercept":0,"scalingFactorViaPm25":1.08}},"atmp":{"correctionAlgorithm":"custom","slr":{"intercept":-0.4,"scalingFactor":1}},"rhum":{"correctionAlgorithm":"none","slr":null}}})";
   cloud_spy::fetch_body_to_write = body;
   cloud_spy::fetch_bytes_to_write = std::strlen(body);
 
@@ -398,11 +398,30 @@ TEST_CASE("FETCH parses supported corrections independently", "[CloudService][fe
   REQUIRE(has_go_config_field(payload.update.update_mask, GoConfigField::HumidityCorrection));
   REQUIRE(payload.update.corrections.pm25.algorithm == Pm25CorrectionAlgorithm::CustomViaPm25Raw);
   REQUIRE(payload.update.corrections.pm25.scaling_factor == 1.08f);
-  REQUIRE(payload.update.corrections.pm25.use_epa2021);
+  REQUIRE_FALSE(payload.update.corrections.pm25.use_epa2021);
   REQUIRE(payload.update.corrections.temperature.intercept == -0.4f);
   REQUIRE(payload.update.corrections.humidity.algorithm == LinearCorrectionAlgorithm::None);
 }
 
+TEST_CASE("FETCH ignores the retired Go custom PM EPA flag", "[CloudService][fetch][correction]") {
+  CloudFixture f;
+  const char body[] =
+      R"({"corrections":{"pm02":{"correctionAlgorithm":"custom_via_pm25_raw","slr":{"intercept":0,"scalingFactorViaPm25":1.08,"useEpa2021":"ignored"}}}})";
+  cloud_spy::fetch_body_to_write = body;
+  cloud_spy::fetch_bytes_to_write = std::strlen(body);
+
+  A::set_armed(f.cloud, true);
+  A::set_was_armed(f.cloud, true);
+  A::set_post_due(f.cloud, 999'999'999);
+  A::set_fetch_due(f.cloud, 0);
+  A::run_once(f.cloud, 1000);
+
+  const FetchConfigEventPayload &payload = f.mock_rtos.last_event.fetch_config;
+  REQUIRE(has_go_config_field(payload.update.update_mask, GoConfigField::Pm25Correction));
+  CHECK(payload.update.corrections.pm25.algorithm == Pm25CorrectionAlgorithm::CustomViaPm25Raw);
+  CHECK_FALSE(payload.update.corrections.pm25.use_epa2021);
+}
+
 TEST_CASE("FETCH rejects one malformed correction but keeps valid siblings",
           "[CloudService][fetch][correction]") {
   CloudFixture f;
diff --git a/products/go/tests/go_local_api.tests.cpp b/products/go/tests/go_local_api.tests.cpp
index dcf945e..a1a6702 100644
--- a/products/go/tests/go_local_api.tests.cpp
+++ b/products/go/tests/go_local_api.tests.cpp
@@ -100,13 +100,12 @@ LocalServerConfig pm_standard_config(const char *value) {
   return config;
 }
 
-CorrectionEntry custom_pm25(double intercept, double scaling_factor, bool use_epa2021) {
+CorrectionEntry custom_pm25(double intercept, double scaling_factor) {
   CorrectionEntry entry{};
   entry.algorithm = "custom_via_pm25_raw";
   SlrParams slr{};
   slr.intercept = intercept;
   slr.scaling_factor = scaling_factor;
-  slr.use_epa2021 = use_epa2021;
   entry.slr = slr;
   return entry;
 }
@@ -389,7 +388,7 @@ TEST_CASE("Go local API maps the supported active config subset") {
   CHECK(config.corrections->pm25->algorithm == "custom_via_pm25_raw");
   CHECK(*config.corrections->pm25->slr->intercept == -1.5);
   CHECK(*config.corrections->pm25->slr->scaling_factor == 0.5);
-  CHECK(*config.corrections->pm25->slr->use_epa2021);
+  CHECK_FALSE(config.corrections->pm25->slr->use_epa2021.has_value());
   REQUIRE(config.corrections->temperature.has_value());
   REQUIRE(config.corrections->temperature->slr.has_value());
   CHECK(config.corrections->temperature->algorithm == "custom");
@@ -435,7 +434,7 @@ TEST_CASE("Go local API translates one atomic supported update") {
   partial.touch_led_intensity = 2;
   partial.buzzer_enabled = true;
   Corrections corrections{};
-  corrections.pm25 = custom_pm25(-1.0, 0.25, true);
+  corrections.pm25 = custom_pm25(-1.0, 0.25);
   corrections.temperature = custom_linear(2.0, 1.1);
   corrections.humidity = custom_linear(-3.0, 0.9);
   partial.corrections = corrections;
@@ -466,7 +465,7 @@ TEST_CASE("Go local API translates one atomic supported update") {
   CHECK(request.config.corrections.pm25.algorithm == Pm25CorrectionAlgorithm::CustomViaPm25Raw);
   CHECK(request.config.corrections.pm25.intercept == -1.0f);
   CHECK(request.config.corrections.pm25.scaling_factor == 0.25f);
-  CHECK(request.config.corrections.pm25.use_epa2021);
+  CHECK_FALSE(request.config.corrections.pm25.use_epa2021);
   CHECK(request.config.corrections.temperature.algorithm == LinearCorrectionAlgorithm::Custom);
   CHECK(request.config.corrections.temperature.intercept == 2.0f);
   CHECK(request.config.corrections.temperature.scaling_factor == Catch::Approx(1.1f));
@@ -484,7 +483,7 @@ TEST_CASE("Go local API preserves absent active correction siblings") {
   fixture.service->set_access(ConfigAccess::ReadWrite);
 
   const LocalServerConfig partial =
-      correction_config(custom_pm25(1.0, 0.5, false), std::nullopt, std::nullopt);
+      correction_config(custom_pm25(1.0, 0.5), std::nullopt, std::nullopt);
   require_status(fixture.service->submit_config(partial), ConfigSubmitStatus::Accepted);
   const LocalApiRequest request = fixture.receive_request();
   CHECK(request.config.update_mask == field_mask(GoConfigField::Pm25Correction));
@@ -765,7 +764,7 @@ TEST_CASE("Go local API validates strict correction shapes") {
   Fixture fixture;
   fixture.service->set_access(ConfigAccess::ReadWrite);
 
-  SECTION("PM custom requires all coefficients and EPA flag") {
+  SECTION("PM custom requires both coefficients") {
     CorrectionEntry entry{};
     entry.algorithm = "custom_via_pm25_raw";
     entry.slr = SlrParams{};
@@ -774,23 +773,28 @@ TEST_CASE("Go local API validates strict correction shapes") {
                    ConfigFieldId::CorrectionsPm25);
 
     entry.slr->scaling_factor = 1.0;
-    entry.slr->use_epa2021 = false;
     partial = correction_config(entry, std::nullopt, std::nullopt);
     require_status(fixture.service->submit_config(partial), ConfigSubmitStatus::InvalidValue,
                    ConfigFieldId::CorrectionsPm25);
 
     entry.slr = SlrParams{};
     entry.slr->intercept = 0.0;
-    entry.slr->use_epa2021 = false;
     partial = correction_config(entry, std::nullopt, std::nullopt);
     require_status(fixture.service->submit_config(partial), ConfigSubmitStatus::InvalidValue,
                    ConfigFieldId::CorrectionsPm25);
 
     entry.slr->scaling_factor = 1.0;
-    entry.slr->use_epa2021.reset();
     partial = correction_config(entry, std::nullopt, std::nullopt);
-    require_status(fixture.service->submit_config(partial), ConfigSubmitStatus::InvalidValue,
-                   ConfigFieldId::CorrectionsPm25);
+    require_status(fixture.service->submit_config(partial), ConfigSubmitStatus::Accepted);
+    CHECK_FALSE(fixture.receive_request().config.corrections.pm25.use_epa2021);
+  }
+
+  SECTION("PM custom ignores the shared EPA flag") {
+    CorrectionEntry entry = custom_pm25(0.0, 1.0);
+    entry.slr->use_epa2021 = true;
+    const LocalServerConfig partial = correction_config(entry, std::nullopt, std::nullopt);
+    require_status(fixture.service->submit_config(partial), ConfigSubmitStatus::Accepted);
+    CHECK_FALSE(fixture.receive_request().config.corrections.pm25.use_epa2021);
   }
 
   SECTION("linear custom requires each coefficient") {
@@ -866,9 +870,8 @@ TEST_CASE("Go local API validates strict correction shapes") {
   }
 
   SECTION("non-finite and float-overflow coefficients are rejected") {
-    LocalServerConfig partial =
-        correction_config(custom_pm25(std::numeric_limits<double>::infinity(), 1.0, false),
-                          std::nullopt, std::nullopt);
+    LocalServerConfig partial = correction_config(
+        custom_pm25(std::numeric_limits<double>::infinity(), 1.0), std::nullopt, std::nullopt);
     require_status(fixture.service->submit_config(partial), ConfigSubmitStatus::InvalidValue,
                    ConfigFieldId::CorrectionsPm25);
     partial = correction_config(
diff --git a/products/go/tests/go_settings.tests.cpp b/products/go/tests/go_settings.tests.cpp
index 477a9e3..a472acc 100644
--- a/products/go/tests/go_settings.tests.cpp
+++ b/products/go/tests/go_settings.tests.cpp
@@ -128,7 +128,7 @@ class FakeConfigStore : public ConfigStore {
   std::size_t _write_attempt_count = 0;
 };
 
-static constexpr std::size_t GO_SETTINGS_WRITE_COUNT = 33;
+static constexpr std::size_t GO_SETTINGS_WRITE_COUNT = 32;
 
 // ============================================================================
 // Defaults — load from empty store returns struct defaults
@@ -415,7 +415,8 @@ TEST_CASE("cloud control permits only an exact local recovery update", "[setting
   }
 }
 
-TEST_CASE("measurement corrections round-trip as grouped settings", "[settings][correction]") {
+TEST_CASE("measurement corrections round-trip and ignore the retired PM EPA flag",
+          "[settings][correction]") {
   FakeConfigStore store;
   GoSettings original;
   original.corrections.pm25.algorithm = Pm25CorrectionAlgorithm::CustomViaPm25Raw;
@@ -430,12 +431,15 @@ TEST_CASE("measurement corrections round-trip as grouped settings", "[settings][
   original.corrections.humidity.intercept = 1.5f;
 
   REQUIRE(save_go_settings(store, original));
+  bool retired_use_epa2021 = false;
+  REQUIRE(store.get_bool("mc_pe", retired_use_epa2021) == ConfigStoreResult::NOT_FOUND);
+  REQUIRE(store.set_bool("mc_pe", true) == ConfigStoreResult::OK);
   const GoSettings loaded = load_go_settings(store);
 
   REQUIRE(loaded.corrections.pm25.algorithm == original.corrections.pm25.algorithm);
   REQUIRE(loaded.corrections.pm25.scaling_factor == original.corrections.pm25.scaling_factor);
   REQUIRE(loaded.corrections.pm25.intercept == original.corrections.pm25.intercept);
-  REQUIRE(loaded.corrections.pm25.use_epa2021 == original.corrections.pm25.use_epa2021);
+  REQUIRE_FALSE(loaded.corrections.pm25.use_epa2021);
   REQUIRE(loaded.corrections.temperature.scaling_factor ==
           original.corrections.temperature.scaling_factor);
   REQUIRE(loaded.corrections.temperature.intercept == original.corrections.temperature.intercept);
diff --git a/products/go/tests/local-server-integration/ago_local_api.py b/products/go/tests/local-server-integration/ago_local_api.py
index 2977c0f..ca2c4fe 100644
--- a/products/go/tests/local-server-integration/ago_local_api.py
+++ b/products/go/tests/local-server-integration/ago_local_api.py
@@ -213,13 +213,9 @@ def _validate_correction(entry: object, measure: str) -> None:
 
     assert isinstance(slr, dict)
     expected = {"intercept", "scalingFactor"}
-    if measure == "pm25":
-        expected.add("useEpa2021")
     assert set(slr) == expected
     assert _is_number(slr["intercept"])
     assert _is_number(slr["scalingFactor"])
-    if measure == "pm25":
-        assert isinstance(slr["useEpa2021"], bool)
 
 
 def validate_config(payload: dict[str, Any]) -> None: