Won't boot past AT&T screen sometimes won't boot at all.

[ShonsuStL]

So I'm using a S4 active, no roots or anything like that. The only new software I had recently downloaded was "Last Empire War - Z", but I had uninstalled it before the problem started.

The phone was behaving normally and then it just shut down. When it started back up again it said "System software not authorized by AT&T has been found on your phone". It stayed on that for a short time and then restarted again. When it came back up it said Samsung custom and a unlocked padlock.

I couldn't get it to go past that screen until I found out how to do a factory reset. Which I did, but it still won't boot up past the AT&T screen. It either freezes up there, on the Samsung logo, or on the padlock screen mentioned above. Sometimes it won't power on at all.

I'm hoping someone can help me, I really like this phone and don't want to spend the money on a new one. Any and all help is greatly appreciated.

EDIT: Perhaps it's some sort of power/battery issue? I switched batteries and now it's constantly rebooting itself. Usually only getting to the Samsung logo before freezing/restarting, but occasionally it gets to "Optimizing app" but freezes at "10 of 147"

 

[B. Diddy]

Welcome to Android Central! Are you certain the phone has never been rooted? Did you buy it brand new from AT&T, or refurbished or used from elsewhere?

Try reinstalling the firmware using Samsung Kies or Samsung Smart Switch.

 

[ShonsuStL]

Bought it new from AT&T about 2 years ago. I can give t hat a try when I get home, but I'm not sure the PC is recognizing the device for some reason.

Thank you though! I am definitely going to try it and keep all my fingers and toes crossed.

 

[B. Diddy]

If Kies or Smart Switch don't work, you could try using Odin: http://forums.androidcentral.com/am...w-flash-stock-rom-via-odin-new-interface.html