Chosen Solution
I replaced the screen on my iPhone 6s and I followed to ifixit handbook and everything and when I went to power the screen on. I started getting a boot loop. I took it to a repair shop and they said they couldn’t find what was wrong. I’ve tried all the boot loop methods online and I’ve tried restoring. Nothing has worked. I’ve been told the mother board has been fried by research and I don’t understand why that’s so. Nothing looks broken everything looks the way it should
I know you said you tried all of the boot-loop suggestions but you don’t tell us which ones. So for the record, I’ll post some ideas below and tell us if there’s anything in there that you haven’t tried. That way we’ll be able to help a you a bit more. A few things to consider: 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 probably have a logic board issue. If you are uncomfortable doing these steps, consider finding a repair shop that does micro-soldering; they can go deeper if the problem is not modular in nature.
It may be caused by the baseband PMU pseudo soldered.
