Starting with Android 5.0 Lollipop and continuing through Android 6.0 Marshmallow and beyond, Google implemented strict security protocols.
(Device Mapper Verity) is a security feature introduced by Google to protect system partitions from tampering. It checks the system partition's integrity at boot time. If you modify the system (e.g., by rooting), DM-Verity will detect the change and prevent the device from booting—often leading to a bootloop or a "Verity mode" error. no-verity-opt-encrypt-6.1.zip download