How To - Downgrade The PS3 CFW From 4.82 To 3.55 OFW Step By Step - YouTube
PS3 System Software 4.89 Update Live, Don't Update Your Firmware! | PSXHAX - PSXHACKS
PS3: CFW Evilnat 4.90 released - Wololo.net
PlayStation 3: Sony releases Firmware 4.87 for their 14 year old console - HFW 4.87.1 is already out with SEN Enabler already being updated to spoof FW 4.87 - Wololo.net
How to download and install PS3 games without jailbreak via USB - YouTube