Hey there! I have the same cd/dvd-rw device as you. It's installed in a Sony Vaio VGN-S2VP laptop. I recently discovered that I have big problems burning DVD's. I am also looking for the same firmware as you. I found this problem described in detail in several forums. Some blame it on hw error, some on firmware and some simply think it is because of bad DVD discs (Some brands of DVD's are bad and won't work right on this unit). I am beginning to believe that the last reason is the most likely. If you find the firmware update, please respond in this forum or send a private message.
I got reponse from Sony Customer Service, v1.01 f/w is posted here: http://www.css.ap.sony.com/VAIO/download/downloadList.asp?cat=VAIO Notebook&Model=VGN-S38TP But some forum mentioned latest f/w should be v.1.05. Any one have this?