All android by default have dm-verity check on system modification detection to break things like

  1. Root
  2. Kernel modification
  3. Malware protection
  4. Customization
  5. Android payment system protection
  6. NFC payment system protection.

  • By defaults DM-VERITY enabled on most android 5.1.x and newer.
  • Samsung adopted dm-verity and used Device Root Key(DRK) to make DM-Verity Sign.
  • Due to DRK is already available on most models (at factory programming time ) of samsung & all platform so it was easy to implement dm-verity which is default enable on all 5.1.x and newer, samsung did not loos time and used same keys for dm-verity.
  • Old time DRK was only used for REACTIVATION session challenge calculation. (even if its not used all device have drk long before dm-verity come,older )
  • DRK provide keys for dm-verity to make encryption enable and full check on system or user data encryption.
  • GCPro can fix your device DRK to close one which factory have in technically its fix DM-Verity too.
  • GCPro fix issue for ever its not temp repair or bypass or skip.

FAQ Repairing DRK damaged handset is on most case as below.

1) Q: Working device wiped efs. How to fix DRK?

1) Ans: Select box port uart interface. Connect C3303K cable to phone.Use battery tape on BSI or *#0*# to enable uart without root.Select any model in gcpro.Select DRK Repair & wait till process finish. Your phone is repaired.
Reflash if need.

2) Q: Non Working device wiped efs. How to fix DRK?

2) Ans: 1). Easy way is get factory COMBINATION file extract bootloader file (aboot.mbn or sboot.bin) make zip flash with gcpro samsung zip flasher.
or make tar flash with odin. Now use same step as 1Q.

2). If phone warranty is already void use any custom kernel flash custom recovery and install custom kernel zip. This will bypass drk check and let your phone start.
Now use same step as 1Q.

3). Download Full 4 part firmware which include CSC,AP,CP,BL .Full flash with odin. Wait for restart and go to recovery,wipe data,cache & reboot phone. put in download mode again reflash AP firmware only.
Check if its start normally if yes use same step as 1Q.

If some reason uart can't be enabled by keycodes use ENABLE UART option must root phone.

If some reason phone can't be rooted can't enable uart can't start on normal mode. Only way to fix such case is via COMBINATION flash special bootloader (aboot.mbn or sboot.bin) file.

3) Q: How to fix DRK via adb?

3) Ans: 1). Please root phone & make sure its stable on enable usb developer mode select option in samsung tab DRK Repair adb Press start