You can search XDA for more info, check in Galaxy S3, S4 or Nexus 5 forum
My customized MOTO X from verizon not taking a GSM sim in india.
I tried many sims from different carries, but failed.
It showing full bars with carrier logo, but no calls and sms, only data is working.
When i tried to call someone it shows "Mobile Network not available".
I check IMEI, it is in good condition
and one more thing
When i putting my IMEI on imei.info
It showing XT1055 which is us celluar.
But my one is XT1060
I have bootloader unlocked, flashed cyanogen, sprint rom, roggers rom but no luck.
and my moto x is working with CDMA OMH sim
I do not why it is acting like a us celluar MOTO X which accepts only CDMA sims
Now i am on 4.2.2 Verizon ROM, GSM sim is not working, Showing "Mobile network not available"