5.00m33

Ok so I picked up a copy of Final Fantasy IV Complete (UMD) and upgraded my 5.00m33 to Prometheus 4. I inserted my UMD of the game and it still wants me to upgrade. How can I get around this?

Is this possible im sort of new to hacking and i have seen most of the good themes are for 5.00m33 and i dont know if its possible to install on my 6.39 Pro i have a PSP 3000 (Gran turismo edition if that helps) and i really want the Large Original III theme.

I'm staying on 5.00m33-6, because homebrew (and therefore emulators) work better among other little things, but I want to use that new Popsloader pretty badly. I think there was a way to do dual-boot cfw's before, but I never tried it and the tutorial for it I found seems pretty out of date. Is...