Hacking System menu and Rockband Questions

[ramymason]

I have two different questions!

Whats the difference between having, System Menu 4.0 , 4.1 and 4.2?
The only game i cant seem to play is Wii Sports Resorts and I dont even have the WII MOTION + yet so..

Is there a way to play rockband DLC songs straight trough the SD card?
Like on Guitar hero 5 or something like that!

Thanks in Advance!

 

[ramymason]

And where can i upgrade from 4.0 to 4.1 and .2

I cant find that tutorial...