I was struggling with BIOS upgrades for our new Dell servers, as there were no bootable ISO for BIOS upgrades.
After searching for DOS bootable ISO media I have found FreeDOS project. Unfortunately FreeDOS 1.1 LiveCD image is not available on freedos.org.
After modifying standard fd11src.iso image I finally achieved what I needed.
To add your own files to the iso, just use trial version of Magic ISO Maker (300MB maximum), or some similar program.
Just put your custom files in FREEDOS folder and after booting you will be able to run them in DOS environment.
After boot process is complete run dir command to see what files are in current directory.
On the following picture you can see that Dell BIOS update utility – M620-0~0.EXE is present in the directory.
The only thing left is to execute it:
This Bootable DOS ISO was tested on HP, DELL, Supermicro iKVMs and on VmWare.