HTC One frozen on "Quietly Brilliant"
I don't know all of the right lingo but I will try to give you as much info as I can. (btw, I DID search the forum and I couldn't find this exact problem discussed before, but if it has been please direct me!)
I just picked up my phone and it was stuck on the "quietly brilliant" screen. I let it sit for about an hour after that and checked it and it was still there. I pressed and held the power button down to reboot...froze at the same screen. After some research I figured out how to do a factory reset and still freezes at the same screen. It did show a black screen with the red triangle and exclamation point for a while (I'm guessing that that is HORRIBLE) but now it's just frozen at the quietly brilliant screen again.
The phone is not "rooted" (I don't even know what that is but I hear people mentioning that all the time so I thought I would disclose that.)