Difference between Multiburner UJ-842D, UJ-842S, UJ842

[fortune500]

I`m in Tokyo and I see for sale three different UJ-842 models here. Does anyone know the difference in the models other than price.

I have a T42 for which I currently have a UJ-822S and have just installed firmware version 1.05. Since this time I have been burning nothing but coasters. I have looked everwhere for firmware 1.03. Does anyone know where it can be found and how to overwrite 1.05 firmware

Thanks