I took the liberty of swapping out the F1 in slot 10 with a module that was in a bag with a piece of masking tape that said "new firmware". It reports a firmware revision of 0xf1e1 on the portserver console during initialization (the same rev as the rest of the installed F1s).
So far I haven't seen any more lock-ups. (Fingers crossed.)
The serial number on the OLD F1 (the one with problems) was 10N2LE. It is now in the anti-static bag of the replacement F1 and is lying flat on top of the other modules in the cardboard box to the left of the computers in the Hall.
The serial number on the NEW F1 was 10L079.
A copy of this log entry has been emailed to: saw@jlab.org, rom@jlab.org