iPhone 6s Stuck In Restart: Error (6)

Last night, I plugged in my fully functioning iPhone 6s to charge. I awoke to the phone stuck eternally in restart mode with the black screen and Apple logo. I cannot Manually Restart, place the phone into Recovery Mode or even Reset to Factory Settings secondary to an Error (6). The Genius Bar tells me this is likely a problem with the phone's USB port, how can such a problem occur overnight while I am not even using the phone and when it was completely functional the months prior?