I have customers Samsung S5 Active that every min would boot loop. After 24 hours I got it to update and did 4 system restores. I used Samsung Kies and Smart switch to try and repair and nothing. It has a brand new battery in it and no damage to the phone. I have noticed tho that if its plugged into a computer it does not restart, Unplugged and plugged into a charger on the wall it restarts. Any thoughts or ideas apart from wrapping it in C4 and watching it explode