Years ago I use to use Freedos (linux that acts like dos and is compatibles as dos for most applications ) as a dos alternative for stuff like this. Best alternative would be if you were able to make a bootable floppy first and then add the flash utility and rom file to the floppy if space allows and then boot off floppy and then run utility against the rom file to push it. Some flash utilities have a backup method that will write the current rom file to floppy as a means to resort back if you ever needed to space on floppy permitting.
Thats exactly what i did. I made the floppy bootable and there was a program Asus offers called AFUdos. I Backed up the BIOS on the Floppy and then Installed the New BIOS from the floppy since i couldnt find a way to boot this old timer from USB. The System installed the update just fine, and booted into windows XP no problem. Another Success in the books, haha.
The computer runs nice with a different PSU so its far more quiet aswell. Just for kicks i popped in a 40Gb drive and installed Windows 2000 Sp4. It runs, but firefox seems to crash it haha. Oh well.
Again, thanks for the help.