Got my PSP GO Today :) it has custom firmware 6.61 : r/PSP
PSP: First hacks for the new Firmware 6.61 - PRO CFW & Downgrader updated! - Wololo.net
How To Update Your PSP TO 6.61 Official Firmware in 2021 - YouTube
4 Ways to Upgrade Your PSP Firmware - wikiHow
PSP update: 6.61, firmware, PlayStation
PSP Firmware Update 6.61 | GBAtemp.net - The Independent Video Game Community
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
4 Ways to Upgrade Your PSP Firmware - wikiHow
UMD drive doesn't work after updating to 6.61 Infinity PRO CFW : r/PSP
How to Update Your PSP Firmware
Special Edition. Modded Sony Final Fantasy PSP 3000. 6.61 CFW - Etsy
How To Downgrade PSP 6.61 To 6.60! (Chronoswitch Downgrader) 2017! - YouTube