PSP Firmware 6.60 Released » Brewology - PS3 PSP WII XBOX - Homebrew News, Saved Games, Downloads, and More!
Why do so many people prefer 6.60>6.61? : r/PSP
Infinity 2.0 released for the PSP, allows for persistent CFW on all models of PSPs on 6.60 and 6.61 | Page 2 | GBAtemp.net - The Independent Video Game Community
PSP - POPSloader 6.60 PRO (PS1 on PSP) | PSX-Place
PSP 6.60 PRO - B9, B10 CFW installation [Very Easy] (PSP 3000, 2000, 1000 and PSPGo) - YouTube
Updating The PSP System Software to 6.60 / 6.61 - pspunk