It took me a while to figure this out, but here it is:
My Sony DW-Q30A wouldn't write to DVD-R's, showing them as closed when they were new off the spindle, but with all space free.
I crossflashed to the then-current Lite-ON SHW-1635S testing firmware, reset learned media and HyperTuning data with the EEPROM utility, uninstalled the secondary IDE channel and rebooted (this is key!) and everything was good.
I ran in to a problem when flashing to the current testing firmware in that I forgot I had forced XP to redetect the drive/IDE channel, and again it showed DVD-R's as closed with a single session with no data on them. After messing around for a good hour I came across this. Apparently redetecting the drive/IDE channel is key to learning it's capabilities... or something to that affect. Of course, no other drive I own has run in to this problem, so it's a little hit and miss. Still, I hope this helps someone frustrated with a great drive out there.