I get the error reproduced below when I combine osm and contour lines precompiled tiles for the map of all Asia. Command line used is: java -Xmx27G -ea -jar mkgmap_trunk.jar --gmapi --max-jobs --index --latin1 --code-page=1252 --description="OSM-$MAPA-Topo" --family-name="OSM $MAPA Topo" --family-id=3$FID --product-id=1 --product-version=$VERSION --series-name="OSM-$MAPA-Topo" --area-name="$MAPA" --overview-mapname=$ABR-3$FID --overview-mapnumber=653${FID}000 --road-name-config=$CONFIG --x-mdr7-del=GRADE0,GRADE1,GRADE2,GRADE3,GRADE4,GRADE5,GRADE6,GRADE7,UNNAMED --show-profiles=1 tmp/551${FID}*.img curvas/602${FID}*.img typ/$ABR-3${FID}.TYP Exception in thread "main" java.lang.AssertionError at uk.me.parabola.imgfmt.app.trergn.TREHeader.readFileHeader(TREHeader.java:107) at uk.me.parabola.imgfmt.app.CommonHeader.readHeader(CommonHeader.java:95) at uk.me.parabola.imgfmt.app.trergn.TREFileReader.<init>(TREFileReader.java:56) at uk.me.parabola.mkgmap.combiners.FileInfo.treInfo(FileInfo.java:300) at uk.me.parabola.mkgmap.combiners.FileInfo.imgInfo(FileInfo.java:283) at uk.me.parabola.mkgmap.combiners.FileInfo.getFileInfo(FileInfo.java:156) at uk.me.parabola.mkgmap.main.Main.endOptions(Main.java:612) at uk.me.parabola.mkgmap.CommandArgsReader.readArgs(CommandArgsReader.java:125) at uk.me.parabola.mkgmap.main.Main.mainStart(Main.java:144) at uk.me.parabola.mkgmap.main.Main.main(Main.java:115) I use the same command for many other maps, including big ones like Europe or North America without problems, only Asia fails. I can provide all input files if necessary, but they sum several GB.