Alot of the guides floating around showing how to flash back to stock rom is incomplete ( missing a few steps ) and will result in boot loop most of the time. the correct procedure is : Part 1 : Setting up Fastboot. That is it, Fastboot tools is setup. Proceed to next guide. Part 2 : Flashing guide. after trying EVERYTHING else, this is the method that worked for me, i tried to cover every step possible ( alot of the other guides skipped few steps and that is where i got problems ). hope this helps. ( PLEASE BE AWARE : This will remove recovery and root. if you flash back to stock rom using this method you will have to root your phone again. It will still be unlocked, just recovery and root will be removed. to re add recovery and root check part 3 below. ) Part 3 : Add recovery and root access back after installing stock rom. it is recommended you update superuser to newer version and also install busybox. Now that you have recovery installed you can also flash custom roms again. I STRONLGY recommend once you reach this step that you make a backup of your rom via the recovery menu, that way you dont have to go through all this pain again next time. The End !!!