Didn't work for me. The first thing it brings up is "Starting Guided Access" on the reboot and I can't do anything. Maybe I am doing it wrong or am just too slow to try and close the Safari window (Safari was the locked in app). Apple support said restore as "New phone", disable setting, and then restore from a back up. Sounded wrong but I tried it. As soon as I restore from back up it is back at the "Starting Guided Access" again. Had no choice but to restore to factory settings and rebuild phone from scratch. Kiddo lost a few photos but had all the contacts backed up to iPad and music in iTunes so it wasn't too painful.