It seems instead of using dm-verity table, Android Verified Boot 2.0 only uses hashtree whose root hash is stored in vbmeta partition and vbmeta is signed by the OEM.
Hashtree also doesn't have to be appended with each partition because integrity can be verified by reconstructing the hashtree in memory at boot time and comparing its root hash with the one stored in vbmeta.
Does it need dm-verity table or only hashtree in the footer of each partition?