# Generate your own 2048-bit RSA key avbtool make_vbmeta_image --key custom_rsa.key --algorithm SHA256_RSA2048 \ --include_descriptors_from_image boot.img \ --include_descriptors_from_image system.img \ --output custom_vbmeta.img # Flash it fastboot flash vbmeta custom_vbmeta.img fastboot flashing lock # Lock the bootloader with custom key Now ro.boot.vbmeta.digest will match the hash of custom_vbmeta.img . Note: Google Play will still detect a custom key, but device integrity is cryptographically sound. Myth 1: ro.boot.vbmeta.digest is the hash of my boot partition. No. It is the hash of the descriptor table that contains the hash of the boot partition. It is one meta-level higher.
Minimum libavb version: 1.0 Header Block: 256 bytes Authentication Block: 576 bytes Auxiliary Block: 2048 bytes Public key (sha1): 7c2d...f3e9 Digest: c9664cf7e1fcf30c7bc1e62f477b14cdb7dcc0cdacd0d9d0f0e0e2b0f2a2e2e2 This "Digest" value must match ro.boot.vbmeta.digest on a locked device. To keep a valid digest on a custom ROM (usually for enterprise MDM control): ro.boot.vbmeta.digest
Before Android 8.0, Verified Boot used dm-verity but lacked a unified structure for managing different partitions. Google introduced , which uses a data structure called VBMeta to store cryptographic digests (hashes) of multiple partitions (boot, system, vendor, dtbo, etc.). # Generate your own 2048-bit RSA key avbtool