not only "pirated" games.... i remember i used to boot some mp3/mpg players and misc apps coz i never got "diy-selfboot" working...
cd-r media were a bit expensive here... it was safer to burn it "bootable" than trying to make it selfboot and having a not-working-at-all disc
it was a shame that dc couldn't read rw media.
i dunno if there's some way to make utopia bootdisc work on nulldc, but, tooday it's easier to make the disc selfboot using all that tools available...
visit
http://dreamcast.dcemu.co.uk and take a look at homebrew apps there...