I recently tried to watch a few DVD's with the drive in my computer. That didn't work so well; towards the end of the "file" was the drive not able to read the frames any more. Maybe this has something to do with the second layer on the disk or something with the security on a DVD.
But anyhow I thought it was maybe a good thing to try to update the firmware of the DVD drive to see if that helps.
I have, as Linux advertises, a HL-DT-ST DVDRAM GSA-H12N in my linux computer. This is relative old LG made drive with a Pata interface that can read and write DVDs next to CDs.
Looking for a firmware upgrade showed only a windows utilities for firmware upgrades. The new firmware was packed in "GSAH12N_UL02.exe". I couldn't get it working under Freedos, because it explicitly needed windows. And with wine I only got an error message / no response at all. But I had not much confidence in wine for this hardware job, which made that I started to do some Google search.
This question on launchpad gave me a hint how I could get it working. I did needed to install the mfc42.dll with help of winetricks.
Then I only needed to do the following to update the firmware:
sudo chown -R root ~/.wine
sudo wine GSAH12N_UL02.exe
sudo chown -R $USER:$USER ~/.wine
I did had to add a disk to the drive to make sure that the windows program could find it.
After the reboot is my DVD drive indeed advertising the higher firmware number UL01 is now UL02. However I am still not able to read the complete DVD. That will be the next thing to sort-out.