How To Update Your PSP TO 6.61 Official Firmware in 2021 - YouTube
PSP Custom Firmware Guide For All Models 2022 - pspunk
So I downloaded the 6.61 update and when I try to install it it displays this error and I don't have a custom firmware so If anyone know how to solve this
Release: Infinity 2.0 – Enables Permanent 6.6x Custom Firmware for all PSPs! - Wololo.net