Ok, I see that I cannot have USB and SATA hard drives together. Either USB (with Knoppix v3.4) or SATA (with Knoppix 3.7) I have to live with that.

And now the next problem (or question)
Playing withe cheatcodes:
testcd
I am checking my CD (v.3.4) from O'Reilly's knoppix book. Usually the disk works fine. (Besides problems some of them I have posted here, but I do not think they originated from the bad CD copy)

While testing I got messages, that /boot/isolinux.bin and /knoppix/background.jpg failed MD5 check.
But the final messge stated: Everything looks OK

Is it OK? Can I ignore failed files? Or there is a problem, which I didn't see yet?

TIA