@adi
Do you mean as Boki has interpreted above that you want to move or put additional maps onto the card.... or do you want to add maps to the internal memory of the device itself? I'm thinking it's the latter although that's an odd problem to have if you've properly followed my previous advice regarding use of OSM mapping data so i'm guessing that it's only a file placement or naming problem seeing the map works on the card ok.

The nuvi 2xx5 series can use map IMG files in 2 places on internal memory, those are either in the [Only registered and activated users can see links. ], or multiple IMG files in a root folder named "Map" (i.e.: Map\*.img) where <any_name>.img can be used (e.g. "India_OSM.img" and limited, as i vaguely recall, to 11 characters in the file name). Alternatively, the two traditional Garmin namings of gmapprom.img or gmapsupp.img may be used instead, placed directly in .System folder (e.g.: .System\gmapprom.img).

If neither is indeed your problem, you must give more precise info on what you're facing here.