They are copy protected
I also tried to make a backup copy in case my £230 quids worth of maps gets zapped.
There is a possibility THIS
software may copy them. It is the software people use to make personal backup copies of copy protected Nokia N-gage MMC games.
You must have a identical blank MMC card size, then goto disc tools, then clone disk (ctrl-D)
Ive not tried it yet, but would be keen to know if it works.
Of course i never would condone making illigal copies of navionics cards, but you are within your legal right to make a personal backup copy.
If this thread is a bit dodgy, please remove it admin.