Howto: Prepare USB key with FreeDOS using FreeBSD

CyberLeo Kitsana cyberleo at
Sat Oct 13 06:43:37 PDT 2007

O. Hartmann wrote:
> Does anyone do have an idea?

Ah, the disproportionate march of progress...

The easy way out would be to procure a USB floppy drive. If the machines
support booting from a USB stick, they can handle booting a USB floppy
in legacy mode.

If you're really bent on using a USB thumbdrive, you're in for quite a
ride. Due to the way DOS is designed, it needs a pretty nonstandard
(nowadays) method of booting.

You could 'format' the thumbdrive with FAT12 or FAT16 and put the files
on there, but you would need to find a way to do so from within DOS
itself, as neither Linux nor FreeBSD can create FAT filesystems that
boot DOS.

Your best bet is to use an already existing bootable DOS floppy image,
loading the files onto there (using mdconfig to mount it), and using
GRUB (or another modern boot loader) and memdisk (part of syslinux) to
boot the floppy image off the thumbdrive. This worked for me when
building a thumbdrive capable of booting Norton Ghost, PM8, FreeDOS, and
a few other DOS-only utility diskettes. I believe it's also the method
used by the Ultimate Boot CD.

Good luck!

Fuzzy love,
Technical Administrator
CyberLeo.Net Webhosting
<CyberLeo at CyberLeo.Net>

Furry Peace! -

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