Thanks guys.
I found that switcher, and would go for it if it truly broke the data pin connections. That's what I need. I e-mailed them for specifics.
Fix the bug is easier said than done

. It's an old Emac computer and an M-Audio interface. Apple doesn't respond to 'old' model problems, and the forums came up empty. M-Audio gave me the standard "no notes for that problem.. try re-installing".
dkatz42, I tried building a small switcher with the 'break one of the pairs" idea in mind. Didn't work. I wasn't aware that FW needs wrapped pairs for the data. Gonna pull it apart today, rewire, and see if that gets it working.
Best, Paul