Not necessarily. Legacy devices (Android 7 and below) don't have AVB. Also, some OEMs (e.g., Samsung with Knox) implement their own verification ( ro.boot.warranty_bit ) and may not propagate the standard AVB digest. However, a missing digest on a modern (Android 10+) device usually indicates a corrupt or disabled verification chain.

During boot, the hardware root of trust validates the signature of the vbmeta partition itself.

img file using Python tools to view individual partition hash descriptors? Share public link

# 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

The value of ro.boot.vbmeta.digest is a to the state of all protected partitions. Because vbmeta itself contains hashes of boot and system , a change in any verified partition would alter the vbmeta image, thus producing a different digest.

Think of vbmeta.img as the "master key" or the "certificate of authenticity" for your firmware. It contains:

: Refers to Verified Boot Metadata, the structural backbone of Android Verified Boot (AVB) 2.0.