The word "brick" gets tossed around way too often, imo. You cannot brick your device by flashing a recovery. Bricking most often occurs with modifying radios, etc. Being that there is no S-OFF for the HTC One yet, nobody will be able to do that. However, it is only a matter of time for that is accomplished.
Back onto the topic - did you create a backup of the stock ROM? You could restore that to get ADB/MTP back up and running again.
I talk to corporate like a BAWSS!
DEVICE ► Nexus 5 / Nexus 7
ROM ► Dirty Unicorns
KERNEL ► Franco / Glitch