Hey!
I'm not sure if you got some work already or gave up on this, but I do have a stock file posted that you can work on.
viewtopic.php?f=47&t=14590viewtopic.php?f=47&t=17639I also have a small repository of more information about the hardware the bin somes from as well as more rom dumps. I don't mind posting it here, but let me know if that would be helpful too!