Something

#! /bin/sh

diskname=`basename "$3"`
rdisk=`df | grep "$diskname" | awk '{print $1}'`

echo $rdisk
umount -f "$rdisk"
dd if=/usr/standalone/i386/boot1h of=$rdisk bs=512 count=1
/usr/sbin/startupfiletool $rdisk /usr/standalone/i386/boot
mount -t hfs "$rdisk" "$3"
echo "startupfile done !"
sleep 20

exit 0


Jul 22 11:10:02 localhost /Volumes/leo/private/tmp/scripts.Dxpj/./preinstall[509]: /dev/disk2s1 /dev/disk0s4
Jul 22 11:10:02 localhost /Volumes/leo/private/tmp/scripts.Dxpj/./preinstall[509]: umount: /dev/disk2s1\n/dev/disk0s4: not currently mounted
Jul 22 11:10:02 localhost /Volumes/leo/private/tmp/scripts.Dxpj/./preinstall[509]: dd: unknown operand /dev/disk0s4
Jul 22 11:10:02 localhost /Volumes/leo/private/tmp/scripts.Dxpj/./preinstall[509]: Usage: startupfiletool [-v] <raw device> <file>
Jul 22 11:10:02 localhost /Volumes/leo/private/tmp/scripts.Dxpj/./preinstall[509]: mount_hfs: No such file or directory
Jul 22 11:10:02 localhost /Volumes/leo/private/tmp/scripts.Dxpj/./preinstall[509]: startupfile done !