Following is confirmed to work for android 10.
./download_android_9.sh
; or
./download_android_10.sh
; if docker is not installed:
sudo apt install docker.io
sudo usermod -a -G docker ${USER}
newgrp docker
; build and run container:
./build.sh
./run.sh
; in the container:
/build-android_9.sh
; or
/build-android_10.sh
; boot from rescure sd card, and run /usr/bin/install_android
; boot from mmc into android
; Settings => About Tablet => Build number
; Keep on tapping until you see a prompt that says "You are now a developer!"
; Settings => System => Advanced => Deveoper options => OEM unlocking
adb reboot bootloader
sudo fastboot oem unlock
; wait... after reboot
adb reboot bootloader
./flash_android_10.sh