When I crank the engine with the 788ci powered up the screen hangs up sometimes to the point that no buttons on the unit work. The only way I can get to unit to work is to unplug and replug it. I have a 997 on the back and have never had this issue with it. I have since replaced the battery for the heck of it and went through all connections three times. Has anyone else had this problem and what am I missing?

Thanks