[AC Question]

My phone died last night while I was asleep. I plug it in this morning and then turn it on after a little while. It comes up to a screen telling me to "Type password to decrypt storage" and as you can guess I've never encrypted anything so I don't have a password.

So I get the phone to load into Bootloader.
I try to factory reset and it tells me ***TAMPERED*** ***LOCKED*** ***Security Warning***
Well, I'm at a complete loss as to what to do.

I got the phone last year from AT&T. It's not stolen. It's not second-hand.
It's stock. I've never tried to root it or do anything but use it as intended.
So I'm at my wit's end trying to figure out what to do.

I can't use my phone to do ANYTHING. It's S-On as well.
I can't install stuff on it like ADB to help me fix problems because I'm locked out of doing so. Is there any hope for this?

[Rukbat]

Bring it to AT&T and ask where the nearest Device Support Center is (it might even be in that store). Ask if they could just do a factory reset for you, since the phone just corrupted memory by itself. (If you don't let the battery drop below 40% - which you shouldn't - things like this don't happen.)

It's a crap-shoot. They may reset it for you even if it's out of warranty, if there's a fast way of just pushing a couple of buttons. All AT&T DSCs are good, some just have more compassionate employees than others.

(Or check out our HTC One M7 - Android Forums at AndroidCentral.com or the M7 forum on XDA Forums. Someone may know a button combination that will work. I don't have an HTC, or I'd probably know - finding the hidden little things is one of the things I do with a new phone.)