De-Dummy a game
 

Is it possible to remove the dummy data in a Dreamcast Backup? I currently have it in CDI format, but apparently it's not so hard to convert it into whatever format you need. So is it possible?

Yes it is.

You need to extract all files + CDDA with CDMage (or whatever you want), delete the dummy file (it's sometimes named "00Dymmy.dat, but is always big and full of the same character), and then remake your CD with any methode you want (Echelon's methode for example).

I never tried to delete a file using Daemon's tool. Maybe it's possible. Install the tool, mount your image, delete your file, make a copy. I don't know if it works.

Anyway, why do you need to do that ?

well, the Image i got was dummied for a 700mg disc, but I only have 650, bleh.

Ok, that's a good reason. ;)