OneOS runs a second Android system next to One UI on a rooted Samsung Galaxy and switches between the two without flashing anything. One UI stays installed; the other system lives in a folder on the phone and starts on One UI's kernel as a container with its own zygote and system_server. You switch from the OneOS app and come back with Back to One UI (the OneOS app inside the other system) or by holding Volume Up + Volume Down for 3 seconds.
OneOS started from OneLineage by WeWaffles, and builds its guest images with MysticGSI. See Credits.
Warning
Experimental. It can break your phone's data. Do not try this unless you know what you are doing. OneOS replaces core parts of a running system as root. During development a guest system reached One UI's data and deleted app data and photos, and a guest once took over the phone's lock-screen hardware slot so that One UI could not unlock until a factory reset. Both are guarded against now, but untested phones and images can fail in new ways. You must back up your accounts and data first, and remove the screen lock (PIN, pattern, password, fingerprint, face) before switching. Only use a phone you can afford to reset. Nothing here is supported by Samsung, Google or OPPO.
App version 0.4.40. Samsung flagships with Snapdragon, plus the first five Exynos phones and (0.4.33) the first MediaTek phone; root is required (tested with KernelSU; Magisk and APatch are detected but untested).
The app now uses an adaptive SESL9 card picker, a new OneOS icon, dedicated setup/update and pre-boot checks, and optional verbose entry/return screens. See the UI gallery for Fold8 cover and inner screen screenshots, and boot handoff notes for the display lifecycle and release packaging requirements.
Where each system has actually started, on our phones and on testers' (One UI 9 throughout). What they reported working, item by item, is in docs/compatibility.md.
| Guest system | Has run on |
|---|---|
| Pixel 11 Fold (Android 17) | Galaxy Z Fold8 Ultra (SM-F976B), Z Fold8 (SM-F971B) |
| ColorOS 17, Find N6 build | Galaxy Z Fold8 Ultra (SM-F976B), Z Fold8 (SM-F971B) |
| ColorOS 17, Find X9 Ultra CN build | Galaxy S26 Ultra (SM-S948), S25 Ultra (SM-S938), S25 (SM-S931), A57 (SM-A576B) |
| ColorOS 17, Find X9 Ultra IN (global) build | Galaxy Z Flip5 (SM-F731B) |
| Infinity-X 4.1 | Galaxy S26 Ultra (SM-S948), S25 Ultra (SM-S938), S25 (SM-S931), S24 Ultra (SM-S928), Z Flip5 (SM-F731B) |
| Nothing OS 5.0 | Galaxy Z Fold8 Ultra (SM-F976B) |
Started is not the same as finished: on Infinity-X the reports so far say calls do not work and SMS only sometimes, which is what the IMS switch in Advanced is for (0.4.31, Infinity-X and HyperOS). On the Z Flip5 the camera was broken in both systems; 0.4.31 carries the fix.
Untested profiles, where the app asks you to tick that you know before switching: Galaxy Z Fold8 (SM-F971) and Z Fold7 (SM-F966), Galaxy S26+ (SM-S947), S26 (SM-S942, SC-51G), S25+ (SM-S936) and S24 Ultra (SM-S928) with ColorOS; the Pixel 11 Fold image on the Z Fold8, the Pixel 11 Pro image on the Galaxy S26 Ultra, S26+ and S26, and the Pixel 9 Pro XL image on the Galaxy S25 Ultra, S25, S25+ and S24 Ultra (the Pixel 11 images need a newer CPU), and from 0.4.30 also on the Galaxy S23, S23+, Z Flip5, Z Flip7, A57 and (0.4.31) A56; and on every Galaxy S phone above, the Find X9 Ultra IN (global) build of ColorOS 17, with Google Play and the Play Store; and on every phone above, Infinity-X 4.1 (0.4.27), a custom Android 17 made for the Find X9 Ultra, with Google Play and Google's apps; and from 0.4.31, on every phone above, HyperOS, Xiaomi's system from the Xiaomi 18 Fold, made for the Galaxy Z Fold8 Ultra and Z Fold8 (its cover screen layout runs on the cover; other phones may try it too, where it runs as a phone). Galaxy S23 (SM-S911), S23+ (SM-S916), from 0.4.29 the Galaxy Z Flip5 (SM-F731, used as a phone on the main screen) and from 0.4.40 the S23 Ultra (SM-S918) are accepted for testing only: their vendor software is too old and the system will most likely not start (One UI comes back by itself; please share the session logs).
Exynos, first runs: the Galaxy S26+ with Exynos (SM-S947B, m2s) with both Find X9 Ultra builds and the Pixel 11 Pro image, the Galaxy Z Flip7 (SM-F766, Exynos 2500) with both Find X9 Ultra builds, used as a phone on the main screen (no cover screen layout yet), from 0.4.29 the Galaxy A57 (SM-A576, a57x) with both Find X9 Ultra builds, the first A-series phone, and from 0.4.31 its smaller sibling the Galaxy A56 (SM-A566, a56x), with the same images, and from 0.4.40 the Galaxy S24 with Exynos 2400 (SM-S921, e1s) with the S23s' images. The Galaxy Z Flip6 (SM-F741, Snapdragon 8 Gen 3 like the S24 Ultra) takes the S24 Ultra's images but HyperOS from 0.4.40, untested, used as a phone on the main screen. The S26+ and Z Flip7 test sessions fixed the first Exynos problems (the phone restarting after the switch); every system on Exynos is still untested. Each of them also offers Infinity-X.
Release notes are in changelog.md.
Known open issues for each system are in docs/pixel-guest.md and
docs/coloros-on-fold.md.
Everything else (other Exynos phones, other models, other images, other Android versions) is refused by the app's compatibility checks.
Run OneOS Probe on it. It is a separate read-only app: it changes nothing, and it strips the IMEI, phone numbers and Wi-Fi names from its report (it needs root to read the system). Tap Run tests, then Send to the OneOS team (from 0.4.29), or Share and post the zip with your phone model in Phone reports in the OneOS Telegram group. New releases are announced there too. Probe is in the same download folder as the app (see the latest release).
Before anything else (do not skip these):
- Use a tested phone. The systems above have only been tested on the phones listed next to them. On any other phone the app warns you, and things may not work.
- Back up your accounts and data. Samsung Cloud, Google and Smart Switch, plus photos and anything else you can't lose. OneOS guards One UI's data, but it is experimental.
- Remove your screen lock. Settings › Lock screen › Screen lock type › None or Swipe: no PIN, pattern, password, fingerprint or face. If something goes wrong and the phone boot-loops, a locked phone may need a factory reset to recover. OneOS will not switch while a lock is set. From 0.4.32 Advanced has a switch, under Risky, to do it anyway: your One UI apps and photos are encrypted behind that lock, so a session that leaves the phone unable to accept it is a factory reset, not an inconvenience. Leave it off unless you have a reason and accept that.
- Root, battery and heat. The phone must be rooted (tested with KernelSU), charged to at least 30 % and not hot (under 42 °C).
Then:
- Install the OneOS app made for your phone's series and allow it in your
root manager. From 0.4.25 there are three downloads, each about half the
size of the old single app:
OneOS-<version>-fold.apk(Galaxy Z Fold8 Ultra, Z Fold8, Z Fold7, Z Fold6, Z Fold5),OneOS-<version>-s26.apk(Galaxy S26 Ultra, S26+, S26, Z Flip8) andOneOS-<version>-s25.apk(Galaxy S25 Ultra, S25+, S25, S24 Ultra, S24, S23 Ultra, S23, S23+, Z Flip7, Z Flip6, Z Flip5, A57, A56, A36, A07). Installed the wrong one? OneOS tells you which file your phone needs. - In OneOS open Systems, tap Download on the system made for your phone and download it, on Wi-Fi (3.3 to 5.9 GB).
- Back in OneOS tap I have the file, pick the download, then Set up. Setup takes about 15 minutes: keep OneOS open and the phone plugged in. One UI keeps working meanwhile.
- Tap Switch. To come back, tap Back to One UI in the other system (usually no restart), or hold Volume Up + Volume Down for 3 seconds. Stuck on the logo? Hold Power + Volume Down to restart into One UI.
If your root does not survive a restart, activate it again after you come back.
Tell us how it went (from 0.4.29): after a session, open Last session and tap Send to the OneOS team. Say whether the system started and tick what worked and what had problems (Wi-Fi, calls, Bluetooth, camera and so on); a note and your Telegram name are optional. By default the app sends the short log (the first minutes after the switch and the last two before it ended); it sends the whole session's log when you tick a problem or turn it on. The logs are the same file Share sends, with personal data already removed, and the team keeps reports for 30 days. Share and Save are still there if sending does not work. What everyone reported is counted in docs/compatibility.md: per OneOS version, phone and system, how many reports started and what worked (answers only: no names, notes or phone details).
You can tick what works while you are still in the other system (from 0.4.30): open the OneOS app there and tap How's it going?. Back in One UI, Send to the OneOS team has your answers filled in.
More than one system (from 0.4.30): when you set up another system, the one you had stays on the phone as a copy, with its apps and data. Home lists each of them as Switch to . One tap puts it back (the system set up now is kept the same way), updates OneOS's files in it if they are older than the app (about 2 minutes) and opens the switch. A copy you no longer need can be deleted there too, or in Advanced › Free up space.
Removing OneOS: in OneOS open Advanced › Remove OneOS data. It deletes
everything OneOS put on the phone: the system you set up (with the apps and
accounts in it), older copies and the session logs. It checks first that
nothing of a session is still connected to One UI, and refuses otherwise. One
UI and its data are not touched, and downloaded system files stay where you
saved them. Then uninstall the app as usual. Without the app, the same cleanup
runs from a root shell such as Termux: sh remove-oneos-data.sh (from
scripts/; it asks su for root, and --dry-run shows first what it would
delete).
- On a build machine, an OEM firmware image is turned into a system image
(with MysticGSI, outside this repository), and
scripts/make-overlays.shpatches its framework (switcher/patches/) so it can run as a guest next to One UI. - The app checks the phone and the image (size and SHA-256 against its own
table), then, as root, stages the image and its patched files in
/data/local/tmp/oneos. switcher/assets/oneos_switch.shstops One UI's zygote and system_server (the kernel, vendor services and radio keep running) andguest_prepare.sh/guest_start.shstart the guest's own framework in a mount namespace whose/systemis the image and whose/datais the stage.- Guards keep the guest away from One UI's data and keys: its own vold,
storage and installd guards, no weaver or gatekeeper writes, no new users,
app ids of its own (
docs/app/patch-catalog.md). return_to_oneui.shstops the guest and gives the phone back to One UI, in place when it can and by a reboot otherwise (docs/inplace-return.md).
| Path | What it is |
|---|---|
app-android/ |
The OneOS app and OneOS Probe (Kotlin, One UI look through SESL), the in-guest Back to One UI app, and their tests |
switcher/assets/ |
The session scripts the app ships: switch, prepare, start, return, bridges |
switcher/patches/ |
Framework patchers (Python and smali) applied by make-overlays.sh, and Samsung's installd interface table |
switcher/overlays/, switcher/native/ |
Runtime resource overlays, and the source of the guest zygote launcher (zygote_exec) |
scripts/ |
Build-machine tools: the overlay build, adb deploy for development, log collection |
docs/ |
Design notes, the patch catalog, and what each test session showed |
git clone https://github.com/fahadalijaved/OneOS.git
cd OneOS/app-android
./gradlew assembleProbeDebug # OneOS Probe: needs nothing outside this repository
./gradlew test # unit tests (dash or busybox for the root script tests)Requirements: JDK 21, the Android SDK with platform android-37
(ANDROID_HOME or sdk.dir in local.properties), and internet access to
Google Maven and Maven Central. Details: app-android/README.md.
The full OneOS app (assembleFullDebug, assembleFullRelease) also packs the
package sets: the files OneOS patches out of each built system image, from
../out/overlays*. They are not in this repository. Building the guest images
themselves is not part of this repository either (OneOS's images are built with
MysticGSI, see Credits). What is here is how OneOS patches a built image:
APKTOOL=/path/to/apktool.jar EXTRACT_EROFS=/path/to/extract.erofs \
scripts/make-overlays.sh <system.img> out/overlays # the set for that imageThe build fails unless every file matches app-android/packages/<set>.sha256
exactly, so the sets must come from the same firmware builds. Release builds
are signed with a key from ~/.oneos-release/keystore.properties
(storeFile, storePassword, keyAlias, keyPassword); without it the
release packaging stops. Debug builds use your machine's debug key.
This repository does not host system images, OEM firmware or the patched
framework files built from them, and GitHub releases never carry them. They
contain Samsung's, Google's or OPPO's code. The guest images are built from
the vendor's own firmware outside this repository, and the app accepts only
the builds whose size and SHA-256 it knows
(app-android/core/model/src/main/kotlin/com/fahadali/oneos/core/model/Images.kt).
The firmware/ and out/ folders are ignored by git for that reason.
OneOS is licensed under the Apache License 2.0. Parts of this repository come from other projects and keep their own terms: the OneLineage-derived session scripts (published with WeWaffles' permission). See NOTICE and CREDITS.md.
- OneLineage by WeWaffles: the container hot-switch OneOS is built on. OneOS's session scripts started from OneLineage's, and WeWaffles gave permission to publish this work on top of it, with credit here and in the app.
- MysticGSI (The MysticGSI Authors, Apache-2.0): builds the guest images OneOS runs (not part of this repository). MysticGSI includes TrebleDroid work by Pierre-Hugues Husson (phh) and contributors.
- Project Infinity-X and its Find X9 Ultra build (X9UInfinityX): the Infinity-X system OneOS runs from 0.4.27, unchanged, with OneOS's own framework patches.
- OneUIProject: SESL, oneui-design and oneui-icons (MIT) give the app its One UI look.
- Josh Skinner (@thatjoshguy67): Galaxy Z Fold8 support (pull request #1): the Fold8's Find N6 ColorOS set, its cover display, Quick Settings, AOD, widgets, Pocket Studio and Google fixes, and Samsung's hinge sensor for half-folded postures and the open/close animations in ColorOS and Pixel, which the Z Fold8 Ultra uses too.
- smali/dexlib2, AndroidX, Kotlin, Guava, ZXing and others: the full list with licenses is in CREDITS.md.
Not affiliated with Samsung, Google, OPPO, OnePlus or Project Infinity-X. Galaxy and One UI are trademarks of Samsung Electronics; Android and Pixel of Google LLC; ColorOS of OPPO.
Device-scoped experimental patch sources can be registered alongside the stable OneOS patches. See the patch authoring and publishing guide for supported file schemas, source registration, build examples, testing and rollback.