I tried to translate

mkisofs -o output.iso -b i386/installation/floppy/boot-big.fs \
  -c boot.catalog -l -J -R -L \
  -graft-points \
  /usr/src/releasedir tars=/temp/windoze/tars xircom=/destdir/xircom

into

makefs -t cd9660 -o 'allow-multidot,rockridge,bootimage=i386;/usr/src/releasedir/i386/installation/floppy/boot-big.fs' output.iso /usr/src/releasedir

(adding symlinks for the graft-points), but the CD doesn't boot - what
have I missed?

           no-emul-boot          Boot image is a ``no emulation'' ElTorito
                                 image.

?

Cheers,

Patrick