Which file of OSM-self made to transport into Dakota?

Question:

Just bought my Dakota 20, GPS functions: found myself on the right spot!
But, the world-map is not very precise though.

My first bubble: I generated the .zip map, to be used for the GPS, thanks to Lambertus,
but what do I do: put, copy, transport the unzipped file into the GPS or the zipped file, from which I cannot change its name. Thus I hope to copy the unzipped map, otherwise it is troublesome how to find the right map in the Dakota.

Thanks for a help.

See the FAQ: http://www.dcrainmaker.com/2013/05/download-garmin-705800810.html

“gmapsupp.img” is the file to use. You can rename it, but the extension “.img” must not be changed (note that some older devices require the complete name “gmapsupp.img” - so try that first).
When the device is connected to a computer and visible as a mass storage device, you’ll find there a folder “Garmin”. Just copy the file into that folder.
Better: if your device can use an extra memory card, create a folder “Garmin” on it, and copy the file into that folder on the card: in case of a “broken” map, you can simply remove the memory card, while removing a broken map from the internal memory may be complicated…