ok the dreamcast bios problem seem to be down to which bios is selected in the demul menu.
ive got the correct dc.zip located in the correct folders, but only some of the bios selections seemt to work (eg. katana set5 v1.011 world )
the few of the other ones display missing file errors.
so which bios selection is the recommended/best one?
also - none of the cdi roms play in dremul whereas they work perfectly in nulldc (but nulldc is not as good, and retroarch reicast core just crashes retroarch)
all they do is cause the cd player to appear in dremul.
i would normally assume they arent self-boot, but as i said they work in nulldc so they also wouldnt work there if they were not self boot images.