Ok put your UMD sampler disc in.
When you load something from the game menu it goes through the psp splash screen, where i presume its checking for the signature.
Next go to the Music and video section and load something off the sampler disc through there. The content off the Sampler disc loaded without a splash screen.
So what if we figure out how to load throught the Music/Videos screen?, could it posibly play any unsigned apps like firmware 1.00?