Has anybody tried just writeing to the boot sector of the memory card? i have knowticed that on boot up the psp seems to acsess the memorycard before it is fully booted. rather than guessing random start up buttons looking for a system menu to find out what it's doing, it is just possible that it simply scanns the boot sector of the mem stick on boot just like a pc looks for boot sector code on any inserted disk media...
just a guess, leme know if it works... i dont actuly have a psp to test this thiory :P
This could be a possibility since the PS2 also reads from the boot sector of the mem card, this has allowed Homebrew to be run on the PS2.(I do it, it's cool stuff) Sony have most likely learned from thier mistake and surely it's something devs have checked out already?