Hey!
I had SD1 Plus..and a friend of mine still got a SD1 ...He loaded latest OS for Plus..I think it's 3.0 or something..and it's working perfect.The diference are few butons more and a drum remix option.That makes drums from paterns to be runned with the midifile.
By the way , I still have a nice pack for SD1, with new pianos and guitars..many other stuffs to makeit sound up to date.
Let me know
Vio