I have Walmart Family Mobile, and I've also got a SGH-M919 that is unable to get a GPS lock. I want to return it and I'm very much wanting to be absolutely certain that it is in a state that will be acceptable to Walmart Family Mobile. So far, I have: I have used Odin v3.07 to install TWRP, then did a full backup. Then CF-Auto Root, I then flashed a ROM and reverted to that backup, flashed another ROM, and reverted to that backup again. Now I know I can use Odin to put back the stock TAR for my device, but I do wonder, will Walmart Family Mobile see what I've done, my warranty then being void? Do I need to remove TWRP? Is there a thread that will tell me everything I need to do? If not, I need the low down. UPDATE: I actually need help, thanks. UPDATE: Pretty please? The unroot/fix soft brick guide doesn't include anything about removal of TWRP or returning a device.