The only drawback with "bootfrom=/hda1/path/to/knoppix.iso", where hda1 is an NTFS partition, is that you either have to have the Knoppix CD in the CD drive (you can remove it after it starts, and use your CD drive for other things) or have the (cd)/KNOPPIX/KNOPPIX file saved on another non-NTFS partition. (And if you do that, you don't need the ISO file; you can use the "fromhd=" cheatcode.)

In other words, Knoppix won't start without being able to access that (cd)/KNOPPIX/KNOPPIX file on a non-NTFS partition somewhere.

See this long thread if you're interested.