As one struggling to get a Sony DRU820A to first recognize dual layer media and then burn it…I consulted Sony’s media compatibility document
This document indicates Sony does -not- support their -own- dual layer media for a DRU-820A? This is a bit surprising! Note the date on the document is October 13, 2006.
Coulda sworn I checked their compatility prior to that and Sony DVD+R DL WAS supported. Have they backed off? Am I missing something obvious?