DOS boot disk (for flashing BIOS)?

Deron Meranda deron.meranda at gmail.com
Fri Dec 17 05:52:29 UTC 2004


On Thu, 16 Dec 2004 23:13:09 -0600, Christopher J. Bottaro
<cjbottaro at alumni.cs.utexas.edu> wrote:
> How do I make a DOS boot disk to flash my BIOS?

I agree, that's very annoying.  Some motherboard manufacturers such as
Gigabyte now allow you to flash the BIOS without needing a bootable
floppy at all; just a non-bootable FAT-formatted floppy (with no OS)
which is very easy in Linux.

The big problem is that MS-DOS is copyrighted.  Technically it's very
easy, but legally it's hard for anybody but Microsoft and those that
have signed their name in blood to them to distribute the software. 
The sad part is there's no reason why DOS is needed at all, other than
an incredibly stupid assumption on the part of the hardware makers.

The easiest way to do this is to get any kind of bootdisk from
someplace, even an old one lying around someplace.  Some hardware
components like disk drives often come with boot floppies.  Mount it
under linux and put your files on it or delete unneeded ones.  You can
also copy floppies so you don't mess up your only boot floppy (you
can't use "cp" since you must get the boot sectors).

  # Raw copy of floppy to file "bootdisk.img"
  dd if=/dev/fd0 of=bootdisk.img bs=512 count=2880

  # Raw copy of file "bootdisk.img" to floppy
  dd if=bootdisk.img of=/dev/fd0 bs=512 count=2880

(for the curious 512 * 2880 = 1.4 MB)
On your bootdisk you'll need to be sure to keep the files command.com,
io.sys, and msdos.sys  (I'm not a DOS expert so I may be missing
some).

I always keep a DOS boot disk image around just in case I need it for
some lame motherboard or something.

Some sites which look potentially useful are:
  http://www.bootdisk.info/
  http://www.freedos.org/
  http://www.gknw.com/bootdisk.html
  http://www.wlug.org.nz/SysLinux
  http://www.daniel-hertrich.de/bootdisks/


> Also, the flash files are packed in a .exe file (a self extracting executable, I imagine).
> How do I unpack that in Linux?

Yet another extremely annoying motherboard manufacturer behavior.  I
don't know of a good way to unpack these under Linux (at least without
Wine).  If you can make a boot floppy (see above) and there's enough
space, you may be able to put it all on the floppy, boot into a
minimal DOS, and unpack it from there?


Finally.... COMPLAIN.  I know I've sent messages off to
hardware/motherboard manufacturers several times complaining that
their hardware is Linux-unfriendly because of their BIOS update
assumptions.  For all the smart engineers doing all the electronics,
there sure seem to be an abundance of them making aweful websites and
support software.  Also send thank you's to those companies that do it
right.

-- 
Deron Meranda




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