If you have installed a custom recovery (TWRP) and switched to a GSI (Project Treble ROM), you might have replaced the Samsung bootloader with a generic one. In that case, you can use Fastboot:
Before diving into the Samsung A12 specifically, we must understand the technology. vbmeta samsung a12
vbmeta is the Android Verified Boot (AVB) metadata partition that contains integrity and authenticity information (hashes and signatures) for boot-related partitions. On the Samsung Galaxy A12, vbmeta plays the same role as on other Android devices: it enables the bootloader to verify that boot, recovery, and other verified partitions haven’t been tampered with, enforcing device integrity and secure boot policies. If you have installed a custom recovery (TWRP)
: The vbmeta.img is a cryptographically signed image containing verification data (like cryptographic digests) for the boot, system, and other partitions. On the Samsung Galaxy A12, vbmeta plays the