I have a Blaupunkt 530 unit in the MH that provides the SatNag. The map data etc. is held on a 8gb data card that I update as required. I have another 8gb card and I would like to produce an exact copy of the original. I have copied the good card to the second card and all appears well but try as I might the copy simply does not work when I plug it into the unit. What am I doing wrong?