Dark_AleX has now shared Downgrader Test v0.5 For PSP 2.50/2.60 Firmware which, according to MANY users (including TGMG, LalaMan, Firey, and LAXitives), works 100% with PSP consoles that were upgraded to v2.50 or v2.60 Firmware. However, it will NOT work with TA-082 versions and it’s NOT recommended for users whose FACTORY/STOCK Firmware was 2.50 or 2.60.
Check out the video in action here. Unfortunately the video quality is crap but its proof that it works. This hack was just released yesterday. So to those who have upgaded their PSP to v2.6, you still can downgrade to v1.5 to be able to play homebrew games and also ISO games.
Use this to check if you have TA-082 before you continue.