J727t1 network issu after unlok

Hi everyone:
I need help to fix J727t1 bit1 weak 2g signal after unlock procedure with GCpro.
Proc:
Backup cet/ExynosEFS_Reset/write cert backup/SAMSUNG DRK FIX.
Finally the device is unlocked but weak 2g 900mhz signal and serial number=none
B.R.