Searching for Firmware TU11 (because of problems with Toshiba SD-R5372V, TU15)

My problem:
I udated my Toshiba DVD burner SD-R5372V from FW TU11 to TU15. Now the drive does only sometimes change the booktype of my DVD+R dl discs and unfortunately all my DVD stand-alone players do no more play my movies burned on the double layer DVD. I burned 4 discs with the new firmware (using Nero and Verbatim DVD+R dl 8.5GB 2.4x speed) and only one time the booktype has been changed to DVD-ROM!
When I used TU11, I never had any problems with that. The booktype was always changed automatically by the burner to DVD-Rom.
Does somebody know a solution for my problem?

Does somebody own the firmware version TU11??? I need it to flash my drive back! That is the only solution that I see. So please send it to:

Thanks in advance!