Default [Q] Trouble getting stable ROM


I need to repair a M7 T-mobile for a friend of mine.
It had sort of killed itself. It didn't want to start up again. So I though wel than just reflash te ROM and it schould be ok.\

The steps I took
  • unlock bootloader
  • flash custom recovry (TWRP)
  • use sideload to flash rom, internal sd was unreachable
  • rom flashed it booted up
  • everything looked good, running stable on the latest sense 6 maximus HD rom
  • tried to instert sim if that would work (there is probalby my mistake, use Vodafone SIM)
  • eversince phone reboots after a minute or so, tried reflashing, full system wipe, everything I could think of

Does anyone have any suggestions how I could fix the reboot problem??
I personaly think it is in the radio wich can't communicate properly with the ROM.
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