For future reference, if you receive an ota on stock rooted phones, it requires the HTC recovery. It hangs while it attempts to load stock recovery and will never actually flash.

I'll probably update my evo guide for the M8 if I can talk myself into actually putting some effort, I've grown quite lazy as of late.
DON'T PANIC: A relevant and useful guide to all things root
To anyone who has ever claimed something as idiot proof, clearly you have not met my father in law