[Cooljerk]

I'm working on a really simple Sonic CD hack, but I need help figuring out how to build my modified MMD into a bootable sega CD ISO. I was talking to gerbil in IRC and he suggested simply opening up an existing Sonic CD ISO, parsing the directory table to find the file I'm trying to specifically replace, and then just copying the hex over at that location to overwrite the data.

I'm sure that would work, but I've gotta think there has to be a way to build a custom ISO - after all it was done with both Sonic Megamix and Sonic CD plus plus.

anyone have any information on how this could be done?

[Bgvanbur]

I have rebuilt a Sonic CD ISO using my scdmake script. If you can use PERL (which scdmake requires), I can release my SCDMAKE.CFG file to do this.

The biggest problem with randomly making a new ISO is normal software doesn't handle the IP/SP programs and for Sonic CD at least one of the files needs to be in a specific location (though most of the files uses the ISO file extent tables) since when I sorted the files by filename on the Sonic CD, the resulting ISO would not work.

I second gerbil suggestion since it the easiest. On linux, there is the isoinfo command where you can get the sector locations of the files on an ISO (isoinfo -l -I some.iso). I imagine other operating systems have similar utilities so you don't have to learn how to decipher the file extent tables in the ISO.

[Zycor]

Couldn't you just insert the changed files into an ISO with winrar?

[Cooljerk]

Well after universal suggestion to simply edit the ISO, I've begun doing just that. Big thanks to djohe, btw, who has been helping me with what I've been doing today.

I'm updating the Sonic CD wiki right now.