Default HTC ONE wont boot after kitkat update

HTC One Tmo US fully stock and fully updated:

Ran the update. Verified it was all charged and, after it downloaded the update, left it and returned an hour or so later.

The phone was just sitting at the "HTC quietly brilliant". Left it for another hour and same thing. Did a factory reset and a cache reset. Still wont boot.

Instead of sending in the phone and getting a referb I want to root the device. However I can't turn fastboot off since the phone wont boot fully. Any ideas on how I can get the computer to see the phone so that I can request the token code to get my bootloader unlocked? Please HELP Thanks