I rooted, installed a couple of ROMs with TWRP, due to problems with those, I reverted to a backup. Since then I can't get a GPS lock no matter what I do. Up until I rooted this week, the GPS worked fine. It's hard to believe it's a hardware failure conveniently timed exactly when I rooted. I've been using a GPS Status app to see if any satellites are connected to at all, none are. If I load an app that uses precise location, it will just show Searching for GPS... for 10+ minutes which is when I shut it off. I just did a factory reset tonight, with no effect. I read something that tightening down the screws under the back panel can help, I did find two of the screws about 1/16th of a turn loose, had no effect. I don't believe I have an overheating problem, the screen does get a little warm to the touch but never even close to hot. an old article I found from last spring mentioned that Yahoo Weather app being removed solved a lot of GPS lock problems, but that app isn't included with my SGH-M919. I know that GPS problems are somewhat common with the GS4. I am definitely in need of troubleshooting help. My GS4 is within warranty for another 10-11 months, but I use an app six days a week on the job, it's indispensible to what I do, and I'm sure it would take a week or two to get a replacement.