The DICE PXE service includes an option to boot to FreeDOS. This is a free and compatible alternative to MS-DOS. Its homepage is

Basic FreeDOS option

To boot FreeDOS choose "FreeDOS" from the PXE menu. This boots the machine into the basic FreeDOS floppy image.

BIOS Update option

FreeDOS can be used to update the BIOS on a Dell desktop. (We use FreeDOS because the BIOS updaters for Dell desktops are usable only from DOS or Windows, not Linux.)

At the moment the only such update option available is for the Dell Optiplex 780. To make the BIOS updater available by PXE for a 780, add this to the 780's LCFG file:

!pxeclient.platforms mEXTRA(freedos780)
Having done this (and waited a few minutes for the PXE server to deal with its new profile), the 780 can then be rebooted. Boot into PXE and choose the option "FreeDOS with 780 BIOS update A-14. Choose option 4.". After choosing this option from PXE, choose option 4 from the 5-option list that FreeDOS presents. Once you have the A:> prompt type update.exe to start the BIOS update.

Maintenance of the FreeDOS PXE images

The basic FreeDOS image fdboot.img was downloaded from and is installed by the local freedos RPM.

The Optiplex 780 BIOS update version of the FreeDOS image is made by hand like so:

# mkdir fdboot dos780
# mount -o loop fdboot.img fdboot
Create and mount a 3MB fat image:
# dd if=/dev/zero of=dos780.img bs=1M count=3
# mkfs.msdos dos780.img
# mount -o loop dos780.img dos780
Copy the FreeDOS files and the BIOS updater (previously downloaded from Dell) to the newly created image disk:
# cp -r fdboot/* dos780/
# cp -r O780-A14.exe dos780/update.exe
Unmount everything:
# umount dos780
# umount fdboot
Copy the boot sector from the original FreeDOS image to ours:
# dd if=fdboot.img of=dos780.img bs=1 count=446 seek=62 skip=62 conv=notrunc
(Thanks to for this.)
Topic revision: r2 - 14 Jun 2013 - 10:35:56 - ChrisCooke
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