PS3 Slim/Super Slim exploit leaked, could harm your PS3, hints at cool things coming soon - Wololo.net
PS3 Homebrew Archives - Hackinformer
Downgrading slim to 3.55 | PSX-Place
I purchased a PS3 backward compatible from ebay for a good price and I'm impressed how clean it is. However... It's still on firmware 2.50. Should I update the firmware? : r/PS3
PS3 - PS3 CECH-2504B Flashing 4.82 to 3.55 | PSX-Place