disable-verity on Android-O

[gan]

Android Oreo has separate partition for vbmeta. With 'adb root & adb disable-verity. Do reboot and on booting I see HASH mismatch error on vbmeta partition check AVB_VBMETA_VERIFY_RESULT_HASH_MISMATCH from avb_vbmeta_image_verify function. From the code, adb disable-verity disables the AVB_VBMETA_IMAGE_FLAGS_HASHTREE_DISABLED but not AVB_VBMETA_IMAGE_FLAGS_VERIFICATION_DISABLED/

How can I make disable-verity work on Oreo?

-gan