On certain variants of the M8, there have been a few stumbling points here and there. For the Verizon HTC One (M8), this has been the lack of a functional custom recovery. But now thanks to the work of XDA Recognized Developer simonsickle, there is now a working, unofficial TWRP port for the device.
Pretty much everything works with this port except for ExFAT write. However, read access works, as do pretty much all of the other features you’d expect from a user-friendly custom recovery. And to make things even better, simonsickle has made the device tree he used to compile the recovery available on his GitHub.
So if you own a Verizon HTC One M8 and you want to get in on the custom recovery fun, head over to the development thread and give this a whirl.