Originally Posted by Droosh
I did a clean flash (wiped data, system, internal storage) of the official this morning before all the no data warnings came out. It couldn't activate as we now well know. I struggled with this a bit and clean installing an unofficial nor a 10.0 ROM would get it back.
YMMV, but what worked for me was to NANDROID back to CM10. Then I toggled CDMA subscription (in Mobile Network settings) to NV. I then toggled on and off airplane mode. I then switched it back to RUIM/SIM, turn off airplane mode and PAYDIRT!
I then did a full wipe again and installed an unofficial 10.1 build and it activated right away.
Incidentally, I'm not have any of the problems that people are discussing in the G+ community. It may because of the clean install, the test LeanKernel, or using the 12/12 gapps.
Good luck and happy flashing!
I followed Droosh's fix and it worked for me. Flashed back to a 10.0 backup, did the toggling he said a few times, not sure it was the same order he did it but toggled it back and forth, airplane mode a few times. Might have even done a reboot but that brought back voice and data. Did a 4G speed test.
I then did a factory wipe/cash/dalvik and restored a 4.1.1/touchwiz backup and it also had phone data.
To make it clear, I did NOT Odin anything, didn't flash a 4.0.4 or anything to get it back, just went back to CM10.0 TWRP backup and togged around the things listed above. Everything works fine back on my 4.1.1 touchwiz too when I went back to it via backup.
Just restored my original CM10.0 backup and flashed aerovan's 12-17 10.1 build and it worked fine/had data/voice. I am going back to 4.1.1 for now. Either I don't understand how USB works for accessing the phone storage or it's not working right showing me the full drive both internal and external. Also seemed like my phone reception was weaker, that shouldn't happen should it?
I'll be checking 10.1 out in a week or two after you all have banged around on it! Just thrilled that the bluetooth issue is fixed.