I had Pandorad M33 on old PSP which was made with some neat tool I found but I cannot track it down anymore.

Now, I have only one PSP Fat remaining on version 3.73 without Pandora, turned on 2 years after. I was trying to figure out what do all these latest versions and firmwares and what that stuff does and requires but couldn't figure out. Could anyone point me to simple Tool or Tutorial that just gets me on a Custom Firmware, and allows me to play ISOs without complicating?

After all this time I am lost, so I would really appreciate your answers, thanks!