As an old hand with this, I can be of help perhaps.
While opening and screwing with the mobo can work... it is not the best way, nor even needed.
However, you DO need to be running custom firmware. This is the _only_ way that (excluding the few psp-1000 hacks) you can run unsigned code on a psp.
You say that could not get that working, and as it is a psp-2000, I assume you just made mistakes. No worries, if it still works it can be done.
I will clarify a few things, then get to the help.
1) Be warned, the first time this process is done is hard.
2) Cracking a psp you own is legal, but playing DLed games is not. No exceptions. I cannot help you run that game, but it is as easy as copying it to the right folder.
3) You will need to borrow another psp, one that can already has a custom firmware.
Rather than re=posting things, I will link you to some other sites:
psp-vault.com
In this site's forums there are a lot of good threads, much like this one.
noobz.eu
This site is the ORIGIN of much of the tools you need. But also hard to get around in.
dark-alex.org
The site of the messiah of psp-hacking.
I'll be back here in a while, maybe tomorrow.