Ubuntu :: Grub2 Boot Floppy To Load From USB?

I have a number of legacy pcs upon which I would like to install Lubuntu. None have CDROM drives, but they do have floppy drives. None can natively boot from USB devices. My goal is to boot into Grub2 from a floppy with USB support, but I'm having trouble making the floppy. I've seen recommended a few times a command string something like

Code:
grub-mkrescue --overlay=/boot/grub --image-type=floppy GRUB2.img
dd if=GRUB2.img of=/dev/fd0

But when I go to do this, grub-mkrescue has no --overlay nor --image-type option. My man grub-mkrescue page only lists --modules and --output as options. I have managed to make a floppy using the commands

Code:
grub-mkrescue --output=FILE
dd if=FILE of=/dev/fd0

This disk does boot into Grub2. The problem with this is that I need to add other files to the disk to have USB functionality in Grub2, but this process writes to the floppy in iso9660 format, which mounts as read-only. I have tried to go this route using the mount -o remount option to try to make the fs rewritable, but I also haven't been successful with that (and I think my limited knowledge is restricting me here).

Maybe I can add the correct files to the file output by grub-mkrescue --output before I write it to the floppy, but I also don't know how to do that.

Basically, I'm a little burned out and looking for some direction. Am I going about this wrong? When I try and follow other people's guides, they seem to have options available to them that I don't have. I'm doing all this from my Lubuntu 10.04 live CD, but have found similar things on my regular Ubuntu 10.04 install as well.