My bad that was not exact enough. The pic is generated by nav, but is drawn by tv modul.
I also thought some time before to let the system be shown by the pi, but that requests massive programing. Also it takes some time for the pi to boot.
It would be great to have only the pi as module there. This way you would be able to build in a touchscreen only without the need of any physical button. So you could remove the complete bordmonitor.