Cool dude! You have a s-off deivce!
Anyway, Backup ALL (Apps, contacts, sdcard) data before you start with the following steps -
1. Keep your bootloader LOCKED.
2. Download this firmware
and place it in your fastboot folder. Also download the stock ROM
and place it on your device.
3. reboot your phone into fastboot mode
4. Through cmd - fastboot oem rebootRUU
5.You'll have a black screen on the device
6. Just to be sure, flash the firmware zip twice while in RUU mode. (fastboot flash zip firmware.zip)
7. Now go back to fastboot mode ( Power and volume combo)
8. Unlock your bootloader ( please refer HTCDev for instructions)
9. Flash this recovery
(fastboot flash recovery recovery.img)
10. Extract the boot.img from the Stock ROM zip and flash it through fastboot (fastboot flash boot boot.img)
11. Go into the recovery. Do a Factory Reset.
12. locate the stock rom and flash it. (if it was erased while unlocking the bootloader, place it again)
13. now reboot
14. If all goes well, you'll boot into stock 4.2.2!
15. if you want to receive further OTA updates (if any)from hTC , flash this recovery.
Hope I helped! Feel free to ask any doubt you have!