I'm guessing that if I use the vendor-supplied BIOS flash utility, I don't need to muck around with MTD drivers, right? Looking at the HOWTOs, that method seems to be extremely icky at the moment, requiring kernel source edits. I don't mind getting a single floppy drive, and moving it between slaves for this step.
One of the advantages of LinuxBIOS is you can flash rom in Linux using flash_on and flash_rom which comes with LinuxBIOS. With these utils, you don't need mtd.
-Andrew