PSP: Infinity 2.0 – Permanent 6.61 Custom Firmware for every PSP! - YouTube
Sony PSP CFW 6.61 on PSP-1000 and PSP-3000 – McRetro.net
PSP: 6.61 Infinity - Davee's 'Permanent Patch' for System Software 6.61 - Wololo.net
Guide How to UPDATE to Latest Firmware 6.61 For PSP and How to Fix Error Update 9.90 | Guide How to UPDATE to Latest Firmware 6.61 For PSP and How to Fix
Install PSP 6.61 Pro-C Infinity Custom Firmware | GBAtemp.net - The Independent Video Game Community
Release: Infinity 2.0 – Enables Permanent 6.6x Custom Firmware for all PSPs! - Wololo.net