Oh... I'm sorry... Forgot to explain...
Either copy the file you want flashed to root of your external SD card and rename it to just 0P6BIMG.zip (that's a leading zero, not letter O),
or open command prompt, then do the fastboot rebootRUU , then fastboot flash zip 0P6BIMG.zip and finally fastboot reboot-bootloader.
Sent from my HTC One_M8 using Tapatalk