[webber]

read previous posts
you cannot go directly from gdrom to .cdi if it is the original dreamcast game you have inserted in the cdrom reader and are trying to create an image.
you need to get the games or images from newsgroups,ftps,or other sites etc...
or from someone who has already burnt an image and then just copy the backup to another cd.
cdroms don't read the further information located on the gdrom it can only be read by a gdrom.
all you see on a cdrom reader from the original dreamcast game is the first readable section of the gdrom

anyways
regards
webber