HELP! HTC One M8 (HK)- Botched RUU installation. What now? topic

Help! I tried to update my M8 to Lollipop, much dismay has ensued. Please refer to this thread for the entire story.

All I need to know is if I can reboot into recovery using fastboot. The machine still sees the phone in fastboot mode. Can I boot into TWRP and flash my backup?