mobile

I've had my N6 since they first came out, used it on Verizon without any issue. However, where I'm working now doesn't have Verizon service so I bought a prepaid at&t simcard for while I'm here. Everything worked fine at first to switch between them, throw in the Sim card, switch it to global, everything good. Now however, I don't have the same options, under cellular networks I only have "LTE/3g/2g"... Where before I had " LTE/3g/1x/Global". I've tried to set the option through the testing menu, but it never sticks. I'm on stock rooted 5.0.1. I've tried 5.1, but always caused me issues (no audio, constantly rebooting) plus I like a functional xposed so I always revert back. Any one know how to fix this?