PSP: First hacks for the new Firmware 6.61 - PRO CFW & Downgrader updated! - Wololo.net
Sony Updates Its PSP Console with Firmware 6.61 – Download Links Available
PSP Custom Firmware 6.00-6.61
PSP: Custom Firmwares for Firmware 6.61 possible - Currently being updated! - Wololo.net
How To Update Any PSP To Official 6.61 In 2018! - YouTube
How To Downgrade PSP 6.61 To 6.60! (Chronoswitch Downgrader) 2017! - YouTube
PSP: 6.61 Infinity - Davee's 'Permanent Patch' for System Software 6.61 - Wololo.net
PSP Custom Firmware 6.00-6.61
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