We added booting via the BIOS to 9load specifically for USB (though it may have other uses), so that we wouldn't have to add to 9load and maintain 8,000 lines, and growing, of complex USB code (though that's likely due to the inherent complexity of USB rather than being the fault of those who have contributed USB code). See sdB0 and bios0 in 9load(8). The BIOSes have been somewhat uncooperative, but if you make a USB floppy or USB disk be the first item in your BIOS boot order, remove
*nobiosload=something from your plan9.ini, see the example in prep(8) for how to prepare such a USB disk, and the phase of the moon is right, it should work. It's worked here for us. If we get an EHCI driver written, this will all become much more interesting.
