Ok maybe indeed there is a flaw in the autodetect, based on the output, it seems to only scan /dev/sdaX and did not scan /dev/hdaX.

You might need one of those cheatcode fromhd thingie. Maybe you can try fromhd=/dev/hda3. But the problem might be more complicated than this, as the device files /dev/hdaX might not be present in the knoppix system. Looks like you need a patched minirt.gz.

At the debug shell, try this :-

# ls -al /dev/hd*

To check if the device files are present.

If not, try this :-

# mknod /dev/hda3 b 3 3

After that :-
# mount /dev/hda3 /mnt-system
# exit