The following requirements ensures there is transparancy to the status of the device integrity.
Device implementations MUST correctly report through the System API method PersistentDataBlockManager.getFlashLockState() whether their bootloader state permits flashing of the system image. The FLASH_LOCK_UNKNOWN
state is reserved for device implementations upgrading from an earlier version of Android where this new system API method did not exist.
Verified boot is a feature that guarantees the integrity of the device software. If a device implementation supports the feature, it MUST:
The upstream Android Open Source Project provides a preferred implementation of this feature based on the Linux kernel feature dm-verity.
Starting from Android 6.0, device implementations with Advanced Encryption Standard (AES) crypto performance above 50 MiB/seconds MUST support verified boot for device integrity.
If a device implementation is already launched without supporting verified boot on an earlier version of Android, such a device can not add support for this feature with a system software update and thus are exempted from the requirement.