PCI Controller plus flex cable allows for the addition of a minimal video card. As of 2013, they are running FreeDOS.

CN KBMS2 is the PS/2 keyboard header.

After some trial and error with the creation of this cable (sacraficed a PS/2 keyboard)

The completed cable was shrink wrapped.

I was able to get beyond the boot screen to a C:\ prompt.

Custom cable pinout:

What a mess!

It runs PFsense if you like.

Or you can clone the compact flash disk back to stock. I ripped an image of it while I was in there. The images may or may not be copy-able to another Firebox but I didn’t tell you that.