# Android Verified Boot Android Verified Boot (AVB) is Android’s chain-of-trust framework for verifying boot and protected partition state, with rollback-protection support. ## Role in the stage model AVB separates a read-only filesystem property from an integrity claim. SquashFS, EROFS, ext4, or another filesystem format does not establish authenticity; the relevant evidence is the bootloader trust state, vbmeta and partition verification, signing root, lock state, and rollback metadata. ## Evidence to preserve Preserve the device/build, bootloader lock state, verified-boot state, vbmeta digest and signature information, active slot, rollback indexes, boot warning screen, and originating capture method. ## Evidentiary boundary A reported “green,” “yellow,” or “orange” state is meaningful only with the exact device/build and acquisition context. It does not identify who changed a device or establish whether a change was authorized. ## Sources - [[Index - Stages of Interception#Read-only filesystems are not the security boundary — verified boot is|Stage 4 analysis]]. - Android Open Source Project, “Verified Boot”: https://source.android.com/docs/security/features/verifiedboot - Android Open Source Project, “Boot flow”: https://source.android.com/docs/security/features/verifiedboot/boot-flow