[mkgmap-dev] Problems with multiple maps in one gmapsupp.img

Good Evening, I've just been processing the whole USA and put it all in one gmapsupp.img. Zooming in at two, three places shew that at least the places I visited were working. Then I've added the switzerland file. And exactly at the place where I'm living I've got a gap. There _are_ some parts of switzerland which are available on the map, but there is a gap. What might have caused that? When uploading just the gmapsupp.img generated from the switzerland file all is fine. Is it because I'm using too many maps? About 50 in total. Or because one map is buggy? Total file size of the gmapsupp is at 1.8 GB. Any Ideas? Simon