DMA-support for Compaq CRD-8320B?

Some time ago, I acquired a Compaq 32x CDROM drive, type CRD-8320B, manufactured for Compaq by LG, firmware version 1.09.
The “true” LG version of this CDROM supports UDMA2 (according to the spec’s on LG’s website), while my BIOS autodetects the Compaq CRD-8320B as a mere PIO4 device.

I’m wondering whether the Compaq version is inherently different from LG’s own version (apart from having only 1 instead of 2 buttons) ?

I read somewhere on the net that LG’s firmware version 1.32 for this CRD-8320B adds support for UDMA2 (can’t remember where exactly …). But they warn strongly against applying this firmware upgrade to any non-LG brand version. Did anybody take the leap on a Compaq or other OEM-version ?