SAM.G920f error repair DRK

Checking local file... OK
Searching server... OK
Compare local and server file... OK (up to date)
Searching USB Flash interface... COM10 detected
Setup connection... OK
Reading data from phone... OK
Sending data to phone... OK
Sending data to phone... OK
Waiting ADB device... OK
Reading phone info...
Recovery build version: 6.0.1
Boot version: G920FXXU5EQE5
Platform: exynos7420
Boot serial: 10160aace01e1b02
Product board: zeroflte
Initialization zTool... OK
Running zTool, please wait... OK
Checking DRK status... NG!
Writing DRK... error ()

Done with Samsung Tool PRO v.36.2