I've got the TWRP recovery installed and did the "perm root" thing, which appeared to work as the SuperSU app was in the app launcher.
Now today when I tried to install xposed framework I discovered that the root apparently doesn't work. Opening up the SuperSU application gave this following warning:
"There is no SU binary installed and SuperSU canít install it"
I googled around but didn't find anything concrete on what to do. I did find this one page that has a supposed fix in the comments, which I tried using but that hasn't done anything: http://www.theandroidsoul.com/root-new-htc-one-2014-m8/
I then thought I'd re-do the "perm root" step again, so I tried that using the all-in-one app, but now when I boot the phone up the SuperSU app doesn't show up in the app drawer at all and doesn't appear to be installed on the device at all, but the flashing step in the recovery doesn't give any errors at all.
So I'm stuck and don't know what to do now. I tried manually doing the flashing that the "perm root" step does but that hasn't given any other results either.