This information is taken from the .pdf file manuals\ROMinst.pdf on the PC2 CD-Rom.
There are three software components (Boot Block, Operating System, and Soundware) to the PC2 series, it’s best to make sure they are all updated.
CHECKING THE SOUNDWARE VERSION NUMBER
Press the Global button, then press the Right cursor button until you see Int Sound Ver (Internal Sound Version) parameter. If you don’t see this parameter, your operating system version is older than 3.0, and you need to update both your operating system and soundware version.