the mount(which is compiled into ash) comes with knoppix is quite limited.

you have to do the manual losetup but then there is no losetup in knoppix's miniroot.

I have grabbed busybox and compiled in all the necessary initial commands like mount, losetup, insmod etc and replace the ash used(and thankfully still keep the size comparable with it, so no grow in the floppy image size).

A few weeks ago, someone is so kind to host my version of miniroot but I believe it has gone now. If you have a place which allows me to upload, I can give you my modified version and hopefully all you need to do is to replace the modules(I have my own compiled kernel and drivers like cloop.o and loop.o is very picky, one cannot mix) in it. It also has booting multiple ISO/clooped scripts modifications done.

I have also made some modifications of how to handle the kernel modules in the linuxrc such that I can use one set of kernel(vmlinuz + modules) and still testing out different versions of KNOPPIX, kind of KNOPPIX with my own kernel build. In this way, I only need to rely on KNOPPIX for the package update. So every time a new version of KNOPPIX is out, I just download the ISO image and put it on my harddisk and boot straightly with a new GRUB entry.