You need to sign up as a developer to unlock an HTC bootloader.
There's a full set of instructions on XDA
1) Visit htcdev.com and unlock your bootloader
-sign up as a dev, activate your email, and follow the steps
2) Download twrp from the app store. You won’t be able to run it yet but
you still need it
3) Put the supersu zip file from your computer into
your download folder of your phone
4) Get fastboot & adb running on
5) Now boot into recovery mode by navigating to it on
your phone or using the cmd “adb reboot recovery”
- Once you are here you will see the twrp screen
6a) The way I did it is going into the twrp recovery boot and going to install and choosing
the supersu.zip file I moved to my phone in step 3. After it is done
reboot your phone and now you are rooted.
6b) The other way is to go
to advanced in twrp and enable sideload
- now in cmd type “adb sideload ”
7) If you need to turn S-OFF install sunshine on your phone and it will do it.
- You need to have your phone rooted first to turn your S-OFF with sunshine