Knowledge:- The US Cellular S4 R970 has a CDMA/LTE SIM/RUIM slot behind the battery door. US Cellular CDMA service works on NV mode programming on this device. US Cellular 4G LTE works on the SIM slot. This SIM slot is default unlocked for other network's CDMA/LTE SIM cards. It accepts Verizon, Reliance, Tata, MTS SIM cards on the go. I have not been able to restore data inspite of tweaking build.prop and apns.conf in the etc folder of the system. I have tested the handset on all available CDMA/LTE SIMs and calls and SMS work perfectly. Tested on 4.2.1 and 4.2.2.