Full factory reset

[trickys]

Hi can someone please advice me, like a lot of people I'm having issues with my p4p+ from the app crashing to vision faults, dame bleeping when I turn on the controller to warning notices about wind can't take off alsorts, since doing the updates things have definitely gone a bit odd, my question is how do I do a full factory reboot, ? As I've read this could help ..... but I can't find where to do this on the built in screen... please help...