unxz system-arm64-ab.img.xz
This yields system-arm64-ab.img (typically 1–2 GB).
At its core, this file is a Generic System Image (GSI) compressed using the XZ utility.
In short: system-arm64-ab.img.xz is a compressed, pure Android 12 system image designed to run on 64-bit ARM devices that utilize the A/B partition scheme under Project Treble. system-arm64-ab.img.xz android 12
Using command line (Linux/macOS):
unxz system-arm64-ab.img.xz
Using 7-Zip (Windows): Right-click → Extract here. unxz system-arm64-ab
You should now have system-arm64-ab.img.
fastboot reboot
⚠️ Warning for Android 12: Many A/B devices enforce VABC (Virtual A/B with Compression) . On such devices, flashing a raw system image may fail because the system partition is logically virtualized. You may need to use
fastboot updatewith a full OTA package instead of a rawsystem.img. This yields system-arm64-ab
Flashing a GSI is not for the faint of heart. One wrong command can hard-brick your device. Ensure you meet these requirements:
| Requirement | Description |
|--------------|-------------|
| Unlocked Bootloader | Mandatory. OEM unlocking must be enabled in Developer Options. |
| Fastboot Tools | Platform tools (ADB & Fastboot) installed on your PC (Windows/Mac/Linux). |
| Backup | Flashing a GSI wipes all user data. Backup photos, messages, etc. |
| Treble Support | Your device must support Project Treble. Check using Treble Info app from Play Store. |
| Partition Type | Confirm your device uses A/B slots. Run fastboot getvar current-slot in bootloader mode. If it returns a or b, you’re A/B. |
| Vendor Compatibility | The device’s vendor partition must be Android 9 or higher. Older vendors may cause boot loops with Android 12 GSI. |