Are you saying that by running rockboxdev.sh
No, i did not.
patch and diff are already installed? I tried patch, but all it did was make a blank line and nothing happens.
Oke, from the beginning.
Did you ever compiled a Rockbox source?
Look at: www.rockbox.org/twiki/bin/view/Main/DevelopmentGuide#Setup_Your_Environment
You must set-up an enviroment, but it depends on your PC, Linux or Windows!
I choose first CygWin (i have an windows-PC) and now i work only with VMWare
(coLinux setup fails here, during the installation),
i can advise you, choose for the VMWare, its much faster then CygWin.
Again, if you have a Windows-PC!
Look here: www.rockbox.org/twiki/bin/view/Main/HowToCompile
If you can make a build, then you can try to apply an patch to the source,
but an patch is not always needed, it depends.
Example: i like the REP-patch (search in the forums) so i invoke this one,
because i need this one, just like that!