Updating custom firmware on psp
For this you have to look for the number at the end of the serial code I guess its called at the sticker at the bottom.
You could've avoided repeating yourself if you have mentioned that your CFW isn't there anymore, that you have removed all tracks, completely knew what you were doing when you stopped using "hacked games"... I needed to know what you knew about your psp, but I didn't see that anywhere.
This could be the absolute reason why you can't install the firmware.