Android Source code for UP Squared

soham1

I see that UP2 was supported for Android 7.1 with an ISO image. What is the source code branch you are using? I want to compile Android from source.
I was trying out Intel's Project Celadon which is based on Android stack, but the compiled images do not work on the UP2 board. Has anyone else tried? There seems to be some issue with the bootloader.

Can I get the source code branch for Android (preferably 8.1 or higher) which work on UP2? Would appreciate it very much. Thanks!