mount the /KNOPPIX/boot.img file.
this is an msdos fs.
in it you will find a file named 'miniroot.gz'
decompress it (gzip -d miniroot.gz).
mount the decompressed file - this is an ext2 fs.
then look at the file /linuxrc
this is a bash script that's doing about everything that happens in Knoppix until X starts....


just a quick note - keep in mind that the boot.img file has to stay exactly the same size (1474560, IIRC). if you add some bytes, just remove some remarks, and vice versa - if you remove some bytes - add some padding......