you never need MacOS. if you don't mind trashing any mac partition
table you have attempted to put on there this will do:
dd if=/dev/zero of=/dev/hda bs=512 count=1
that will remove an x86 partition table completely. it will also ruin
a mac partition table (since the signature for mac tables is stored on
the very first byte of the disk)
if you want to preserve the mac table and just nuke the x86 table i
think this will do:
dd if=/dev/zero of=/dev/hda bs=1 seek=446 count=66
doing a quick test this seems to work.