it depends on your psp. for example i am using PSP-2000 which i use firmware 4.01 and for my PSP-3000 i am using firmware 5.03.
New version comes out is the best version but i should be custom firmware because without custom firmware you can not play free games in PSP.
the best firmware is 5.03. if you go to pspslimhacks.com, then look for chcikHEN R2 it will help run homebrew on your psp. for example psptube (youtube for psp cfw)
Yes, you can The firmware goes across board to all models of PSP. This includes the Customer Firmware and the Original Firmware.
The newest known firmware for the PSP is 5.54
Custom Firmware is illegal<-----EDIT:Thats not what he was asking, please asnwer the question
Custom firmware allows you to do things on your psp that you wouldn't normally do. Like playing gameboy games on your psp. Made by psp hackers its your choice whether you trust them or not. If you do the best way to get it is to use a Pandora battery only available at www.pandorasales.com. It only works with psp 1000 and 2000
I'm not sure what you mean by "the mod" but I think you may be referring to a "custom firmware". If so, you can safely format your PSP's memory stick without removing the custom firmware. This is because the custom firmware is stored in the internal PSP flash memory, not on your memory stick. If you want to remove the custom firmware, you will need to just install an official firmware onto the psp. The easiest way to do this is to put in a PSP game that comes with a firmware upgrade and choose that option. Then I would recommend having the psp do a Network Update.
Hacking the firmware depends on the PSP's motherboard, not the current firmware installed. If you're asking whether or not it can be made into a custom firmware, then the answer is yes, but all homebrew would have to be rewritten for it.
I'm sorry, but you can not downgrade it back to firmware 6.2 Any firmware after around version 5.5 cannot be downgraded i think. It also depends whether you have a psp 2000 or psp 3000 I have a psp 3000 and it was too late for me to downgrade
The best place I can think of is websites such as,CraigsList.com,Ebay.com,orAmazon.com
Right now there isn't. If you want to get custom firmware for psp version 6.20 you need to downgrade to custom firmware using a Pandora battery.
You need the latest firmware to access the PSN, you can update the PSP from the XMB.