Posted for posterity:

I bought a DVR-105 (whitebox) a while back, and I'd been having kernel
panics in 10.2.6. After doing some reading I decided to update the
firmware to 1.33 via the instructions here:

(requires booting into OS 9, running the Pioneer-supplied firmware
updater with the firmware file they supply for the PC).

After rebooting in 10.2.6 the drive didn't work any more. Volumes
wouldn't mount and I couldn't even eject/open the drive reliably.

Today I updated to 10.2.8 and everything seems to be fine again. I've
not done a complete test, but I can mount CDs, play audio CDs, and
I've burnt one data CD w/o a problem.