DISCLAIMER: Don’t attempt this unless you know what you are doing. I have never had problems doing this, BUT many things can go wrong and you CAN easily “brick” your hardware. Proceed at your own risk!!

We will be using FreeDOS, a wonderfully free and royalty exempt Microsoft DOS compatible operating system. Licensed under the General Public License (GPL).
Note: As usual, my posts require some knowledge of the command line.

wget http://www.fdos.org/bootdisks/autogen/FDOEM.144.gz
gunzip FDOEM.144.gz
mkdir floppy
sudo mount -o loop FDOEM.144 floppy/
ls floppy

you should see these files:
AUTOEXEC.BAT COMMAND.COM CONFIG.SYS KERNEL.SYS README sys.com

Download your BIOS update file from the manufacturer or vendor.
Note: Sometimes, the update will be distributed as a .exe (Windows Executable) file. Most likely it will actually be a compressed zip archive. You can use unzip to extract the .exe file.

Download the update using wget, then unzip the resulting image file “FDOEM.144″ into the mounted folder: “floppy/”

wget http://path-to-your-bios-update/BIOS_UPDATE.zip
sudo unzip BIOS_UPDATE.zip -d floppy/

In this case, the following files are extracted from the BIOS_UPDATE.zip file:
inflating: BIOS.WPH
inflating: OEMPHL.EXE
inflating: OPTIONS.BAT
inflating: PHLASH16.EXE
inflating: releasenotes.txt
inflating: 1.BAT

now, move to the previous directory (cd ..), and un-mount the FDOEM.144 image:

cd ..
sudo umount floppy/

generate the iso image:

genisoimage -o flashboot.iso -b FDOEM.144 FDOEM.144

Now burn flashboot.iso to CD using wodim:

wodim flashboot.iso

Now you can boot from that cd and run your flash utility!! Read the BIOS update instructions on how to do this..