Android custom partition with AVB

[#1]

Here is simple step to create a custom partition with AVB.
Tested by i.MX8MN EVK and Android P9.0.0_2.3.1.

Create image for xyz partition in 1024MB in Android build output folder

# cd $OUT

# mkdir xyz

# echo "This is test txt file" > xyz/Readme.txt

# make_ext4fs -l 1073672192 -s -a xyz xyz.ext4.img xyz

Apply the attached patch. uboot patch corrects the reading problem on avb footer.

Flash images by uuu

# cd $OUT

# sudo ./uuu_imx_android_flash.sh -f imx8mn

Check result. 

Boot up and mount xyz partition

# cd /data

# mount /dev/block/mmcblk2p14 xyz

# cat xyz/Readme.txt

This is test txt file