Producing coasters while trying to create a self boot image

Hello!
I'm trying to create a self boot image. I downloaded the
dreamcast-kernel.tar.gz from
http://members.wri.com/josht/dreamcast/dreamcast.html, unpacked it and
followed the instructions on Marcus Comstedt's page using cdrecord.
However, the resulting CD-R does not boot on the Dreamcast. I also tried
to create the serial upload slave as described on Marcus' page,
producing some more coasters. It seems as if my Dreamcast is one of
those that will not boot traditional self-boot CDRs. To my surprise I
found a Nero image of dcDivX (http://www.moosegate.com/betaboy/dcdivx/)
which my Dreamcast cared to boot from. Does anybody have a hint on what
I must do to create such an image?

Thanks
Marcus