This is all thanks to @nkk71, btw. Right now the fix is very hacky but I'm sure ROM devs will find a more appropriate fix soon.
I'm not sure if I want to reveal the fix publicly in case HTC's spies are monitoring the thread, lol....probably better safe than sorry. But go visit nkk71's profile and buy him many beers for figuring this out. And also find some posts by him and click "Thanks."
WARNING: Dragons ahead! Anything you flash to your device is done at your own risk!
EDIT: Alright, I'll publish a flashable zip here based on the 1.53.617.5 US Unlocked Edition. I've been testing the mod/hack for a few days now and have seen no ill effects. It should work fine on ROMs using that base.
I have NO IDEA if it'll work on ROMs using an International/Europe base or on CDMA. If you really want to try it, make sure you make a backup first! You will need to "Format Data" in TWRP and flash the standard SuperSU zip to remove forced encryption (or do it manually, if you know how).
Let the bricking begin!
P.S. Thanks of course also go to @Chainfire for SuperSU and su.d!