When you start up the PSP it accesses the duo card for a pretty solid amount of time (more than the system normally takes checking for free data when you pop in a card while it's idling on the menu screen) before the system displays the "Sony Computer Entertainment" post.
So the idea that it's looking for some sort of alterative boot file, before it defaults to its firmware, crossed my mind.
Perhaps if one could replicate the directory system of the psp's firmware on the memory card we might get lucky (not sure if that information is even currently available)
I’ve yet to run my psp through a firmware update check, but does the system restart in the process?
Might lead to a much less risky way to test homemade firmware…
mynineridesshotgun@gmail.com