I just found the Firewire board for my 16.4.2 is available on fullcompass' website, only $48.. I'd been waiting quite some time to either sell my unit with a bad firewire board (after plugging it in upside down and frying it) or just waiting until I can afford a new board because I couldn't justify the shipping and repair costs.

Just a heads up - I guess now that these are so old, Presonus is starting to distribute parts.