Extract GD-ROM files from MAME CHD

The mame CHD dumps are in 2352 format, or "RAW"/"BIN". To extract game files, you first have to get the uncompressed image, chdman comes with mame.

chdman -extractcd input.chd game.toc game.bin

We need to convert this file to a an ISO image, first a cue file to extract the high density track, game.cue:

FILE "game.bin" BINARY
TRACK 03 MODE1/2352
INDEX 01 10:00:00

You may add track 01 and track 02 to the cue file.

Now you can convert it to an ISO image:

bchunk game.bin game.cue game

to inspect the file, use isoinfo with parameter -N45000, this is because the layout is relative to sector 0:

isoinfo -N45000 -i game03.iso -l

Use isoinfo to extract all the files:

isoinfo -N45000 -i game03.iso -x "/NAOMIGD.BIN;1" >NAOMIGD.BIN

The first 16 sectors contains needed data, to extract it you can use dd

dd if=game03.iso bs=2048 count=16 of=IP.BIN

IP.BIN is just a filename, you can call it whatever you want.