Go into settings >power and make sure fastboot is disabled. Turn off the phone (wait 15 seconds after the screen is black and then hold down the volume down button and press the power button. Do not let go of either button) and a menu will pop up after about 10 seconds. Scroll down to factory reset using the volume button and press the power button for enter.
I hope this helps!
The good news is, with this update new Sprint ROMS will start rolling out and that is what I've been waiting for.