The only two files that are different to all the others related to date are "fm_sub.bin" and "GarminDevice.xml", both located in the root directory.
Cause the card works only in one car, but not in other ones, some information is written to the card during first use. Maybe all this information is located in "GarminDevice.xml"?

It would be helpful if someone could upload the content of the root directory from a card that was not yet used in a car.

My goal is to find a way to use one card in different cars, like the Becker Map Pilot, that could be used in more than one car.
In a second step it would be interesting how map data could be updated, cause there is no lifetime map update for the SD-cards.