this fall I installed new firmware for the P4. Now that it is in place all is well except I use the Ipad mini 2 and it does not communicate correctly to the RC.  It works fine on other devices.   Can someone direct me to a detailed but concise tutorial on how to correctly clear out the present firmware and re-install new firmware. The first time was awkward and DJI support did more to confuse the issue rather than clarify.   I would like to follow step by step directions using the DJI 4 or dji assistant 2 but I want to do it right the first time.
Any advice would be appreciated.

There is a thread on here about using GO 3 to rollback to maybe 1.6.0 and then advance to 1.9.3.  It didn't work for me as the prior issues remain of disconnections primarily related to the USB port dropping the line needing to be replugged in flight.  My GO 4 screen remains on, just parts of it start losing settings like EXP settings, users settingss like alitutde, version numbers, aircraft name, C1 gimbal, etc.  Weird stuff.

I don't know if it is GO 4.1.8 or iOS 11.2.  The two together seem out of step for some reason.  Many complain about iOS 11 that their app's are crashing in the Apple forum too.  That and some reports of poor or slow battery charging where some need to unplug and replug the USB on the charger as well to get the charger lightning bolt to display.  Dunno.