Additionally, downloading copyrighted ISOs for PSP is illegal in most regions unless you own the original disc and are creating a personal backup — which isn't possible here since no official PSP disc exists for MK9.
This is legal under fair use in some countries (check your local laws). Never distribute these ISOs.
The download was always a gamble. You’d sit through slow file-hosting timers, dodging pop-up ads for "System Speed Boosters," just to see if the legend was true. The Reality of the "ISO"
: Connect your PSP to your PC and move the file to the ISO folder on the root of your Memory Stick.