If you own a Dell notebook with a TS-L632D CD/DVD drive and use it with Ubuntu Linux then you may have the same problem as me: You can't select the write speed in Nautilus. After hours of research I puzzled together various information I found on the net and now I got it working.
The problem is the Dell firmware. And the solution is to install the Samsung firmware. Unfortunately you need Windows for it...
First of all you must download the latest Dell firmware update for the drive (Currently this is DE04) because it contains the firmware flash tool you will need for flashing the Samsung firmware. Then you must download the latest Samsung firmware. The current SC04 firmware can be found here. But maybe you can find a newer one on the net.
Now unpack the downloaded Dell firmware update and you should end up with a *.BIN file (which you don't need) and a executable with a filename like
SFDNWIN3.27.11.exe. Open a command-line, go to the directory which contains the executable and then start it with the command-line argument
-NOCHECK. This parameter must be upper-case! Now select the Samsung firmware you have downloaded and then write it to the drive. Ignore the Version too old warning which may appear.
When you now reboot into your Linux then you can choose the write speed without any problems. Another interesting phenomena is that suddenly the drive is recognized as DVD-RAM capable:
cdrecord -prcapwith DE04 firmware:
... Does not read DVD-RAM media Does not write DVD-RAM media ...
cdrecord -prcapwith SC04 firmware:
... Does read DVD-RAM media Does write DVD-RAM media ...
Even Windows makes a difference now. With the DE04 firmware the drive was listed as DVD-RW drive. With the SC04 firmware it is now listed as DVD-RAM drive. Haven't tested if it really reads and writes DVD-RAM media but others reported that it works.