[For your information] you won't receive calls on gsm with Cm12.1 nightlies

I've already notified the CM and the DEVs, there is no time line to getting this issue fixed. So if you currently use Cm12.1 nightlies on you Sprint S5, you will NOT receive calls while your roaming on GSM networks. Calls will only come in while connected to CDMA networks. The user will just experience and eternal ring then voicemail. Your phone won't even acknowledge that it received the call.

http://forum.cyanogenmod.org/topic/116364-cant-receive-calls-with-cm121-nightlies/page__st__20