How to put your iPhone or iPad in DFU mode to fix it as a last resort

DFU mode can help you recover your iPhone or iPad using a computer.
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DFU Mode

Make sure to back-up your iPhone's operating systems and functions before committing to this (identical to a "Restore Point" on Windows), just so have a state you can restore your phone in case ...
Ars Technica

iPhone 6s boot loop, fails Upgrade and Restore. D.E.D. Dead?

I have an iPhone 6s that is in a boot loop. The Apple logo comes on for 3-4 seconds, and then it goes off for 3-4 seconds, ad infinitum. I tried a hard reset, and nothing improved. I put the iPhone ...