ATA/66 question

[Biff]

I had a 6.4wd on htp66, used to come up as udma33. I had it set as secondary master. After flashing my mb, it would not recognise it, even in bios, I ended up setting it as slave, did not show up in bios, but windows shows it.
Biff

[MadMatt]

I know ATA/66 drives are backwards compatible with ATA/33 and even EIDE and IDE controllers, but is the reverse true? Can I put an IDE drive on an ATA/66 controller?

Hoping to keep everything (CD-ROM, CD-RW, and HDD) on a separate channel,I tried putting an old 4.3gb drive onto the secondary channel of the Highpoint ATA/66 controller on my BP6 last night - wouldn't recognize it in BIOS or Windows. Tried the 80 conductor ATA/66 cable and a plain old IDE.

Are we talking about a fundamental limitation of ATA/66 controllers or yet another Highpoint bug?