I just had a go at flashing my new HTC One M8, and I'm stuck in recovery mode.
I followed these instructions:
But got the TWRP file from here because the original link was overloaded:
I essentially just ran:
Then installed the SuperSU update zip. Now every time I try reboot into the Android system, it boots into recovery mode. If I boot into the bootloader, I get the option to boot using fastboot but that appears to fail (it returns me to the bootloader after a second). If I select hboot, it says "No image or wrong image!" after trying to load a .nbh file.
BTW, I got the unlocked version from Amazon: amazon.com/HTC-One-M8-Unlocked-Warranty/dp/B00J3554KE/