Since this is a Dreamcast site has anyone considered the development side? Well I'll explain what System Disk 2 is. These discs were used to enable a retail Sega Dreamcast unit to read Sega Dreamcast GD-R media encoded in the same region as the unit. If you ever come across a Propeller arena disk you will need one of these.
Since these disks are rare and go for a lot of money I can give the file to burn to a disk if anyone is really interested to getting a rare disk working.