Sorry by delay.....
Well, the same way i told, you'll need to know how 'the things' works 'cause you'll need to write some code lines to make all things work thogether.
For example, like in the post mentioned above, if you wanna see the GPS result without the original OS, you'll need to write some code, probably in owner assembly, for a especific processor, reading an especific address, wrinting on especific other address that makes display, that need some tratment too, to show the information that you want.
I think like "js" told, not only the LCDs are restricted "debuged", but all other components that is available on a board is not debuged yet. (And unfortunately maybe never will be).