[ROM]|4.20.2013|NOS M7 v2.0.0|(Sense 5.0 JB 4.1.2)Butterfly - Page 2 - xda-developers:
Standard Android wipe rom process -
1. Download the rom and copy to your phone (you've probably done this)
2. Download fastboot tools if you don't have them here
3. Extract the adb folder in the fastboot zip to somewhere (E.g. C:\adb)
4. Open the rom zip and extract the boot.img file to the adb folder
5. Connect your phone to your pc
6. Hold shift and right-click somewhere in the adb folder, select "Open command window here"
7. Restart your phone to bootloader, then select fastboot.
8. Type "adb devices" (don't type the " " for this or the others)
9. It should show your phone's serial number, if not download HTC Sync Manager and install
10. Type "fastboot erase cache"
11. Type "fastboot flash boot boot.img"
12. Type "fastboot erase cache" again
13. Type "fastboot reboot recovery" to get to CWM or TWRP, whichever you have installed
14. Backup your system, data, and cache
15. Factory reset, wipe cache, wipe dalvik cache, format system
16. Install the rom.
17. Reboot and leave it for 10 mins, it will stay on the HTC ONE screen for a while for the first boot