WeWaffles / OneLineage

# OneLineage
Hot-switch between stock **One UI** and a **LineageOS 23.2 (Android 16) GSI** on a rooted Samsung phone, with no reflashing and no second partition. OneLineage stages the GSI under `/data/local/tmp`, pivots into it as a container with its own zygote and system_server, and can hand the screen back to One UI.
If something isn't working and you have a fix feel free to make a pr!
> ## Disclaimer
> **This has only been tested on a single device: a rooted Samsung Galaxy S26 Ultra running One UI 8.5.**
> It may not work on other Samsung models, other One UI versions, or other devices at all. It is experimental, it replaces core parts of a running system, and it can crash, hang or soft-brick your phone, fill `/data`, or break radio/SMS. **Back up everything first. Use at your own risk.**
> Also, I did use AI a fair bit in this project, it would have taken a LOT longer without it.
## Requirements
- A rooted Samsung phone (the tested one is an S26 Ultra on One UI 8.5)
- Enough free space on `/data` for the extracted GSI
- Internet access for the GSI download (LineageOS 23.2 GSI, EXT4, VANILLA or GAPPS builds from SourceForge)
## What's in here
| Path | What it is |
| --- | --- |
| `src/`, `res/`, `AndroidManifest.xml` | The Android app (`com.wewaffles.onelineage`) |
| `assets/master_prepare.sh` | Stages the rootfs, binds the patched files, fixes labels/ownership |
| `assets/master_inner.sh` | Runs inside the container, starts the guest zygote |
| `assets/switch_to_lineage.sh` / `return_to_oneui.sh` | Switch in and back out |
| `assets/zygote_exec` | Static aarch64 launcher for the guest zygote |
| `build_apk.sh` | Builds and signs the APK |
## Patches
### Patched system files (bind-mounted over the GSI)
- `services_patched.jar` over `system/framework/services.jar`
- `framework_patched.jar` over `system/framework/framework.jar`
- `PermissionController_patched.apk`: removes the `android.permission.RANGING` reference so runtime-permission dialogs stop crashing (Samsung's PermissionController needs a permission the LineageOS 23.2 platform doesn't define)
- Optional bind-mounts when present: `framework-res_patched.apk`, `libaudio_aidl_conversion_common_cpp_patched.so`, `libaudioclient_aidl_conversion_patched.so`
### Boot and environment fixes
1. **APEX paths in the container.** Host `/system/apex` and `/system_ext/apex` are bound into the rootfs after the GSI payloads are extracted, so PackageManagerService stops dying in `scanApexPackages`.
2. **SELinux labels on the staged `/data`.** The tree is relabeled like a real `/data` (`system_data_file`, per-package `app_data_file`) instead of `shell_data_file`. Also `setenforce 0` during the takeover and `setenforce 1` on return.
3. **Audio hang.** Host `audioserver`/`cameraserver` are left running (they used to be stopped/frozen, which deadlocked `AudioService`). Only the host zygote is suppressed.
4. **Runaway `sf.log`.** SurfaceFlinger output goes to `/dev/null` (it was growing to hundreds of MB in mi