@foone Honest question:
Wasn't there some trickery with the cable to force modes?
Something like: if DMA req and ack aren't connected, drive reverts to slower PIO, and if 80-connector and i-forgot-which pin is ground, drive enables fastest UDMA speeds above 66?
I remember needing to watch out for these specifics whem buying a CF to PATA adapter in order to get (U)DMA working on a cobbled together home server.