No You don't understand me.
I dekompress the file KNOPPIX from cd to remaster it, but I don't remaster it.
I just comprest it back by mkisofs -R source | create_compressed_fs - 65536 source, or somethig like that, so that I get bak the compressed KNOPPIX file.
Than I make CD with structure like this:
/
KNOPPIX
|
+KNOPPIX (rekompressed file)
+boot.img (from the original KNOPPIX CD)
+boot.cat (from the original KNOPPIX CD)
and boot.img was also given as booting image (e.g. in K3B)

And that CD could not run
If I do it exacly the like that with KNOPPIX file from oryginal Knoppix CD it works.
So it looks like minilinux from boot.img could not get to prepared by me KNOPPIX file.