I think a reply to your question is in post n27
I am also having the problem of not being able to add third party maps to a garmin 7608. It does seem that garmin has actually made contact with openseamap to acknowledge the problem and say they are working on a solution.
I am wondering, aside from problems with third party support in current firmware, do maps such as openstreetmap and openfietsmap typically work in garmin marine chartplotters?
Yes, i'm acutely aware of the lack of compatibility of my current product. but i am wondering if i had a device compatible with third party maps, such as a gpsmap 7000 with older firmware, would openstreetmap work, or is there something inherently different between street and nav maps which would prevent compatibility? I intend to use this chartplotter for off road expeditions....right now trying to decide if it is worth reverse engineering this device, or exchanging it for an older device capable of doing what i want to do.
Garmin GPSMAP 7608, GPSMAP 8212