Background

The Galaxy A20's bootloader has a bug where it refuses to load boot/recovery images that don't contain the SignerVer02 magic and an AVB Footer at the end of the partition with the image's size. This results in the "SECURE CHECK FAIL" screen that we all know and love.

How to fix

1. Download the Python script of this repository.
2. Run python fix_bootable_image.py boot.img fixed.img (replace boot.img with the boot or recovery image you want to fix)
3. Flash the fixed.img image through Heimdall
4. Done!