Quote Originally Posted by Kanopus View Post
I don't thing it's because of NT or non-NT format. Probably your GPS needs see maps, like blue charts. You can experiment with gmaptool. Load img to gmaptool, set advanced and experimental options, go to write tab and try to set TRE parameters to 0-4-23-empty. No guarantee, I can't check it.

If you are creating your own maps with cgpsmapper, then try option MARINE=X in [IMG ID] section.

There is possibility to change map into quasi-NT format with gmaptool, see join tab with experimental option set. But I doubt whether this solves your problem.
hm, i am not sure. i was trying to use "normal" blucharts from mapsource, but the unit is displaying: "map format not supported". what i know the difference between "normal" and g2 bluecharts is that the g2 are in NT format.