If you want, I can:
: This may require using a semi-tethered booting method. For the A12, this could involve flashing a special, patched kernel from the custom ROM community. Some developers have shared such files in XDA forums and GitHub repositories. This is a last-resort solution for advanced users with a device that refuses to boot any custom image.
Custom recoveries alter the recovery partition, triggering AVB.
Before touching the vbmeta image, ensure you have the following ready:
Expected output with custom vbmeta: