So I'm an old fart that hasn't picked up his PSP in at least 3 years. I'm currently running custom firmware 3.71 M33-2. I don't even remember what that means anymore, lol. Anyway, I want to sell my PSP-1000 to make some money for a PSP Go. I just want to restore a factory firmware so I can sell it without having to tell people how to use it or what not to do if they don't want to brick it.
TLDR; how do I install factory firmware on PSP-1000 with 3.71 M33-2?
Thanks in advance for the help.