S6 6.0.1 Downgrade to 5.1.1 Fail

Trying to downgrade 6.0.1 to 5.1.1 cause i unlocked the phone and a few days later the IMEI and baseband say null using Odin v3.10.6 and
G920FXXU3QOLH_G920FNEE3QOL2_G920FXXU3QOKD_HOME firmware file.
The phone says:
Reactivation lock is off and in red after fail
SW REV. CHECK FAIL DEVICE: 4 BINARY: 3
Cant post links or upload pics so wont let me post the odin log any pointers as the phone is uk vodafone. I have tried stock rom and I have tried this software aswell
G920FXXU3COI9_G920FBTU3COJ1_BTU_PAC with ZEROFLTE_EUR_OPEN Pit file and still no joy please help :confused: