Release: Infinity 2.0 – Enables Permanent 6.6x Custom Firmware for all PSPs! - Wololo.net
PSP: First hacks for the new Firmware 6.61 - PRO CFW & Downgrader updated! - Wololo.net
How to Mod Any PSP on Firmware 6.61 or Lower! - Infinity 2.0 Permanent CFW - YouTube
PSP 6.61 Custom Firmware Install on any PSP - PSP, PSP Slim, PSP 3000, PSP Go & E1000 | Digiex
Release: Infinity 2.0 – Enables Permanent 6.6x Custom Firmware for all PSPs! - Wololo.net
How To Update Any PSP To Official 6.61 In 2018! - YouTube
PSP 6.61 Custom Firmware Install on any PSP - PSP, PSP Slim, PSP 3000, PSP Go & E1000 | Digiex
PlayStation Guide
4 Ways to Upgrade Your PSP Firmware - wikiHow
Infinity 2.0 released for the PSP, allows for persistent CFW on all models of PSPs on 6.60 and 6.61 | GBAtemp.net - The Independent Video Game Community
PSP 6.61 Infinity Hybrid Firmware by Davee, LME & PRO CFW Patch | PSXHAX - PSXHACKS