merge 2 geodata.dat files?

[fak3]

as the title said how can i merge 2 geodata.dat files downloaded with gmdl?

[HE3HAYKA]

I tried to do this job mannually by transforming back two PSP maps into *.png tiles. Tons of files.

Moreover, my maps had 2 different zoom levels. It means a lot of 'dirty job': tons of file renaming etc.
But... when I finished it wa worthless - all GPS data has been lost. I've got maps with useless for GPS tracking.

So, I re-downloaded the whole map again with the coverage I needed. Took some time, but it worked - I've got a map of 550MB (already compressed).