Could be a similar problem:

When I start the car, empeg starts, I start gpsapp and everything works fine, the route is displayed.

When turning ignition off (e.g. during tanking or a brake) and on again when empeg has not powered down yet empeg comes back with mp3-screens but not with gpsapp. Holding the knob pressed brings up gpsapp but not hijack menu.

Sometimes gpsapp hangs up the empeg completely during this process.

Juergen