MiWearBridge

An LSPosed module for Xiaomi Mi Band / Vela wearables that hooks Mi Fitness (com.xiaomi.wearable).

It is based on A5245/Wearable-Debug (third‑party quick‑app / watchface / firmware install, log pull, encrypt‑key dump) and extends it with the part that was missing for real third‑party use:

• @system.interconnect bridging — any same‑signed Android app can talk to a watch quick‑app without Xiaomi partner onboarding ("bond").
• Coordinator bindings — many watch quick‑apps → one phone app.
• Periodic watch → cloud auto‑sync, even when Mi Fitness isn't opened manually.

⚠️ Research / personal‑use project. It changes Mi Fitness behaviour at runtime via Xposed. Use at your own risk, on your own device. Not affiliated with Xiaomi.

Why interconnect needs this

Xiaomi's interconnect (watch quick‑app ↔ phone app) officially requires the third‑party app to be authorised by Xiaomi ("bond"). Without it the band silently refuses to route the app's messages — even when package and signature match. The transport itself carries no authorisation: routing is purely by package, and "is this app's companion online" is decided on the phone via syncPhoneAppStatus (device command 20/7). The original failure was simply that Mi Fitness never sent that signal for an unauthorised app (and getCurrentDeviceModel() returned null). MiWearBridge supplies everything the phone side needs so the band accepts the app and opens the channel.

Features

All actions live in a hidden menu inside Mi Fitness: Profile → About this app → tap the User Agreement / privacy line.

Inherited from Wearable‑Debug:

• App — install a third‑party quick app (.rpk). Enter a package name, pick the file (any name works at install; the real package is only needed to uninstall).
• WatchFace — install a watchface file. No package name needed.
• Firmware — install a firmware file. ⚠️ May brick the device — use with caution.
• Pull log — dump device logs to /sdcard/Android/data/<pkg>/files/log/devicelog/.
• Encrypt Key — show the EncryptKey stored for the connected device(s). Format: did: [name, EncryptKey].

Added by MiWearBridge:

• Bind apps to watch — manage watch app → coordinator app bindings. Tap + Add binding, pick the phone coordinator from the installed‑apps list, enter the watch app's package. Remove with ✕. If a watch package is not listed it falls back to itself (watch package == phone package — the default "matching name" behaviour), so simple single‑app setups need no entry.
• Auto‑sync to cloud — toggle periodic sync of watch data to the cloud and set the interval (minutes).

Example projects

batareya16/MiBand8ProHassControlApps** Control Home Assistant from Xiaomi Mi Band 8 Pro

How the bridge works

Inside the Mi Fitness process:

• Redirects the XMS SDK bind target to Mi Fitness and swallows the client‑side not bond exception.
• Forces the XMS service checks (Status results, install/permission checks) to success.
• Returns a real WatchAppItemEntity / WatchAppCapability for bound packages, with the correct SHA‑1 signing fingerprint.
• Fixes WearableDeviceManager.getCurrentDeviceModel() returning null by falling back to the connected device from the manager.
• Announces the app as online to the band via syncPhoneAppStatus — the signal that actually opens the watch‑side channel.

Coordinator routing:

• Watch → phone: remaps the incoming watch package to its coordinator (P2) so messages land in the coordinator's listener.
• Phone → watch: the coordinator addresses a specific watch app with a header @w:<watchPackage>\n in the payload; the hook strips it and routes the message to that app.

Requirements

• Rooted device with LSPosed (Xposed API 82+).
• Mi Fitness (com.xiaomi.wearable);
• Watch quick‑app(s) and the phone app must share the same signing key (interconnect requirement; the fingerprint used in checks comes from the coordinator app).
• For background auto‑sync: set Mi Fitness to no battery restriction.

Build

./gradlew assembleDebug
adb install -r app/build/outputs/apk/debug/app-debug.apk

Scope — what to enable (important)

The module hooks two sides, so for the stock setup you must enable it on both:

1. Mi Fitness (com.xiaomi.wearable) — the server side (forge records, online announce, routing).
2. Every companion app.

Contract for your apps

1. Signing: sign every watch quick‑app (.rpk) with the coordinator app's key.
2. Phone → watch: to reply to a specific watch app, prefix the message with @w:<watchPackage>\n followed by the real payload.
3. Watch → phone: the coordinator's listener receives (deviceId, data) without the source package, so include each watch app's own identifier inside the payload (e.g. a "src" field) to tell senders apart.

Credits

• Built on A5245/Wearable-Debug.
• Reverse‑engineering for interoperability and personal use. No warranty.