n9005 initializing AT Ril … error

Hi z3x guys!
I am trying to write Cert to a N9005 whose imei is null and baseband unknown. I have searched around and tried what others suggested but nothing worked so far. Every time I try, the operation hangs in initializing AT Ril …error. The samsung tool software also stops responding afterwards (I am on the latest version 24.1, if that might help). The phone is rooted and everything is done as instructed. The only thing that seems not ok is when entering *#9090# service shows nothing. The phone connects to the box perfectly though. I also flashed a few official roms but to no avail.
I would really appreciate your help.