There is a small app in the store called "Phone Info". It basically opens up the "Secret"?! menu that takes to a section of the phone not normally accessible. This menu allows much greater control of the phones radios. I have Verizon so I set the phone to "CDMA auto(PRL)" instead of "LTE/GSM/CDMA auto (PRL)". This forces the phone to stay in CDMA mode. I live in a fringe area and this both saves on battery life but also lets me have good phone calls. I mean it is a phone right? Be VERY careful going into that menu you could really mess up your phone choosing the wrong setting. You need to know before going in which setting you want to use.