I have a garmin echomap 43dv and want to add marine maps. The pre-made Europe maps from this site load fine and work great but sadly I don't live there. I've tried to make custom maps of the US east coast following the link to bbbike.org but unfortunately those fail to load. I get an error, "The map file is not supported."
The file is not large (smaller than the northern Europe one I tested). I have tried both UTF-8 and ASCII Garmin OpenSeaMap format and neither works. I really hope someone can help me. Thanks in advance!
I have excatly the same problem with my Garmin GPSMAP 547.