I've built images based on android10 branch. While build is successful, for some reason after the rainbow boot screen the screen remains black after flashing a few times. I'd suspect it's either some changes in elf/bootcode that causes this but I'm not entirely sure. I'll provide my images in the link below for any of you to test, just in case my rpi3 is the one malfunctioning
https://1drv.ms/f/s!AuId3rHqj0kAnCVpKk77jUiwegXg