Limping along with USB

I didn’t have to dig out the other 3.5″ enclosure after all — I switched to a USB connection, and suddenly the Mac can see the hard disk.  I can’t boot from it, though, so I’ve had to rerun all of the updates I’d made since I switched.  But my data is back.  For now, anyway.  With luck, I’ll have some time this weekend to do some better diagnosis.