@tubetime Fingers crossed it's not something that needs opening the enclosure to fix, as doing so outside of a clean room would most likely render it toast (bad sectors developing) a short while afterwards.

i did a little logic analyzer probing. it's waiting like 288ms for the HDD to respond, and when it reads the status register, it gets FAFF. this doesn't really make sense because upper bits should be 000 indicating the drive, not the controller.