Make sure the repo tool is setup as it is described here:
https://source.android.com/setup/build/downloading#installing-repo
Create a directory for holding the sources and then initialize that repository:
mkdir -p ~/BBB-Android
cd ~/BBB-Android
then initialize with our default.xml:
repo init -u https://github.com/opersys/bbb-platform_manifest.git -b master
The name choosen for the directory does not matter.
In that same directory, fetch the sources:
repo sync -j $(getconf _NPROCESSORS_ONLN)
From the directory you created in the steps above, prepare the environment for the build:
source build/envsetup.sh
Run lunch, to configure the build for your target.:
lunch beagleboneblack_sd-eng
(eventually, the beagleboneblack_emmc target will also be supported)
To build the sources:
./build-beagleboneblack.sh
This assumes that the BeagleBone is in its default state, with a bootloader that is able to boot from the MicroSD card. If you need to, restore your BeagleBone to factory default by using this image:
https://debian.beagleboard.org/images/BBB-blank-debian-9.5-iot-armhf-2018-10-07-4gb.img.xz
The script for writing the MicroSD currently assume a 4GB MicroSD. We'll be working on adapting the build scripts to bigger cards in the future. Note that whole content of the card will be erased by this procedure.
DEVICE_NAME here is the filename of the device which corresponds to the MicroSD card. Ie: if the card corresponds to the /dev/sdc, write just sdc there and not the whole path.
scripts/write-sdcard-beagleboneblack.sh $(DEVICE_NAME)
This should be enough for your BeagleBone Black to boot Android.
eMMC support in progress