Looks like bootfrom= went the same way as home= (not supported, no reference at all in /init anymore).

There has been an admission that the cheat code documentation was not updated correctly for 6.0.

It looks to me like

Code:
bootfrom=/dev/sdx1/somewhere/some.iso
could be done with:

Code:
fromhd=/dev/sdx1 knoppix_dir=somewhere knoppix_name=some.iso
but it hardly seems worthwhile.