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My Iphone 5s kept shutting itself off and getting stuck in an infinite loop of rebooting, this went on for about a week and then finally the last time it happened my iphone now just won’t turn on. Every time I try and Turn it on it loads the apple screen for about 4 seconds and then the screen just goes black, but doesn’t completely shut off until about 10 seconds after the black screen appears. I don’t have a computer that is compatible with iTunes so i am not able to recover it that way.
It kinda sounds like the battery is not charging. Can you plug it into a USB ammeter to see if there is any current flow? Otherwise, a bootlooping device can be caused by many things. Try these things (if you haven’t already) to see if anything helps: Try a hard reset (Home & Power button for 10 secs)Use a genuine Apple Lightning connectorUse a genuine Apple charging brick and let it charge overnightTry to connect it to different computers (mac/pc if possible) with an updated iTunesPut the phone in recovery mode (search DFU Mode). Careful, this can reset your data Use 3uTools for putting it in and out of Recovery ModeUse 3uTools to flash the firmware (you can’t downgrade)Check the condition of all the flexes (with magnification)Disconnect the Front Camera Ribbon from the logic board and reboot your phoneDisconnect the screen assembly completely and see if iTunes will recognize the phone. Otherwise, you may have a logic board issue. If you are uncomfortable doing these steps, consider finding a repair shop to do the troubleshooting. A shop that also does micro-soldering can go deeper if the problem is not modular in nature.
