“In an email to the FreeBSD Hackers mailing list, Rink P.W. Springer reports success in porting FreeBSD 5.4 and 6.0 to the XBox game platform:
Over the last 2 weeks, I have been working on a port of FreeBSD for the XBox. […] The port is fully functional. The framebuffer is fully supported, same goes for sound and USB devices (such as an USB keyboard for the console). Only ethernet is missing, currently […]. Also, a live CD has been created […].
It says on the primary mirror that the CD should probably boot on almost any Xbox that “doesn’t block unsigned binaries”. It requires (and comes with) Cromwell, a bootloader BIOS for Xbox, originally used to make it boot Linux.
(Xbox-linux.org is not responding at the time of writing.)