boot - Create a DOS bootable USB drive (16 GB)

I have two computers, both on Ubuntu, and I need to upgrade the BIOS on one of them. I can get a version of DOS and also use UNetBootin with FreeDOS, but I can't copy the BIOS firmware and flash utility to the key because

1. The USB device is 16GB, thus cannot seem be read from DOS


2. The DOS/FreeDOS images don't have enough free space to copy the files

I could try and use a CD to burn the BIOS files, unfortunately I don't have any at hand at the moment (and would need to be a CDR-W as it seems a waste to burn 2.2MB on a 640MB device... to be discarded after, too!)

That being said, I have tried...

• ...to repartition the USB device, with no luck.


• ...using dd to copy the ISO (and even an IMG) over the USB device


• ...directly accessing the USB device from DOS/FreeDOS

No success.

Is it even possible? With USB devices being bigger and bigger, finding a DOS-compatible one seems like a futile initiative, no? Any ideas?