Bonjour Bebopellula.
As far as I can tell the only service menu is:
MainMenu->Setup
press Red button
press Center button
I also have the screen needing to be remeasured due to a circuit board repair/replacement.
Unfortunately, it appears that a separate measuring device from the dealer/installer is required to do this measuring to make the warning “message” at startup go away.
It was designed to have the installer do this measuring when the system was first installed.
I am still waiting to see if there is one still available in North America from my B&O representative to have borrow in order to make that calibration again.