Stuck in bootloop, nothing works!

I guess you are not getting any error messages in iTunes. If you are, please let us know.

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 connector
• Use a genuine Apple charging brick and let it charge overnight
• Try to connect it to different computers (mac/pc if possible) with an updated iTunes
• Put the phone in recovery mode (search DFU Mode). Careful, this can reset your data
• Use 3uTools for putting it in and out of Recovery Mode
• Use 3uTools to flash the firmware (you can't downgrade)
• Disconnect the Front Camera Ribbon from the logic board and reboot your phone
• Disconnect 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.