With Android 12's AOSP source drop yesterday, many were left wondering (particularly those with Pixel devices) when they would get to use a fully complete version of the latest and greatest Android experience. We've already seen a number of beta builds from OEMs like OPPO, OnePlus, and Samsung for select devices, but there are no stable releases yet and there likely won't be for a while. Having said that, the public availability of the Android 12 source code means that custom ROMs are now due to come at any time, and indeed, they have already started appearing on our forums.

An Android 12-based custom ROM is now available for the Redmi K20 Pro/Xiaomi Mi 9T Pro, courtesy of XDA Senior Member abhishek987. The big news here is that the vanilla AOSP ROM seems to be pretty much stable for the most part, although with one big caveat that being the SELinux status is set to permissive in the initial build. The developer has adopted Danny Lin's (AKA XDA Senior Member kdrag0n) open-source dynamic theming solution, as Google has yet to fully open source its "Monet" theming system.

Since this device has multiple regional variants, it is recommended to flash the latest region-specific stable channel MIUI firmware before installing the Android 12-based AOSP ROM. However, do keep in mind that a permissive SELinux environment is not at all meant for being a daily driver. Unless you don't have any problem with running a less secure software, you’re better off not installing it as your primary device.

AOSP 12.0 for the Redmi K20 Pro/Mi 9T Pro || Redmi K20 Pro/Mi 9T Pro XDA Forums

There is no doubt that Android has become more and more modularized since the arrival of Project Treble, making custom ROMs closer and closer to Generic System Images, or GSIs. Thanks to the beauty of Treble, most of the current generation devices with an unlockable bootloader can technically boot nearly fully functional builds based on the latest Android release. This has led to XDA Recognized Contributor AndyYan compiling an experimental Android 12 GSI build from source, which can be flashed on any Treble-compatible device.

The Android 12 GSI build is rather barebone at this stage, but that is alright as we are still in the early days and additional features will be migrated over time. The developer has also created a dedicated repo for the frameworks base patches, so that ROM maintainers can easily cherry-pick and start porting the popular custom ROMs on top of Android 12.

Download source-built AOSP 12.0 GSI

Legendary GSI developer and XDA Recognized Developer phhusson is also working on his own Android 12 GSI, though he has yet to release any builds publicly at the moment. It's still early days for Android 12 custom ROMs, but keep an eye out on your device's forums and you may be surprised by how quickly they pop up.