Another thought or two came to mind...

When it says it's looking in /dev/hdb, does it mean /dev/hdb exactly? Ie without regard to partitions? It seems that it might be since it does find the image later at /dev/hdb4 or /dev/hdb1 depending on whether its the "cd on usb key" or "compact flash hard drive" install methods.

If this has credence as an idea, then how do I solve it? I am going to try building a compact flash hard drive without partitions. I don't know if it's possible, and I doubt that it's going to work, but I am out of ideas. Any thoughts on how to make the boot process try the partitions rather than the raw device?

I have tried BOOT_IMAGE=/dev/hdb4/KNOPPIX/KNOPPIX, but I don't think I have tried it on the compact flash/hard drive install. I will have to try that.

I have tried BOOT_IMAGE=/cdrom/KNOPPIX/KNOPPIX, but is the link between /dev/hdb1 and /cdrom only made after this step?

Thanks again for any ideas anybody might have.