Making BIOS update CDs on a Mac

I use VirtualBox to run Windows to prepare Windows-only BIOS updates for customer computers, especially since floppy disks are so rare now.

Make a folder to work in:

mkdir CD

In the Mac OS Terminal, create an empty floppy disk image:

dd if=/dev/zero of=CD/bios.img bs=10k count=144

Attach it as a floppy image in Virtualbox running Windows. Run the BIOS update disk creator in Windows.

Detach the floppy image, then create a CD image with the bootable disk image:

hdiutil makehybrid -o boot.iso -joliet -iso -eltorito-boot CD/boot.img CD

Then burn the CD:

hdiutil burn boot.iso