OFW psp & CFW psp blogs - Firmware 6.39 ME-5 was develop and release by PSP Developer Neur0n who has decided to release his latest PSP Custom Firmware 6.39 ME-5 for users
PSP Custom Firmware 3.60 M33 Released For PSP Slim - Exophase.com
Custom Firmware Help : r/PSP
PSP Mail-in Custom Firmware Mod Service all Models - Etsy Denmark
PlayStation Portable homebrew - Wikipedia
Firmware, Custom, Installation
PSP: First hacks for the new Firmware 6.61 - PRO CFW & Downgrader updated! - Wololo.net