PlayStation 3 PS3 320GB Console Bundle 10 Games Tested 4.84 Firmware PLEASE READ | eBay
PS3 Firmware 4.88 released, do not update just yet - Wololo.net
Factory Service Mode - PS3 Developer wiki
Downgradable PS3 Models & Base Firmware with MinVerChk | PSXHAX - PSXHACKS
PlayStation 3: Sony releases Firmware 4.86 for their 13 year old console - HFW 4.86 released, SEN Enabler updated & PS3HEN to be updated soon due to no kernel changes! - Wololo.net
How to install Custom Firmware on the PS3 with FW 4.82 - Hackinformer