Replacing PSP system files with other PSP system files?

Alright...well...I had bought a Red PSP, 3000 from a friend a while back. And it had CWF on it, with all these games and sh*t. And then I had bought Kingdom Hearts and I wanted to play it...so me...being a dumbass, accepted the change Sony wanted me to do so I can play the game (Going from 2.00 to like 7.00) And now I miss the games...:/ But the good thing is, my brother has ALL the old PSP files. EXACTLY how it is when I got it. So my question is...what if I copy ALL of the old PSP files that my psp had...and delete (or move) the and updated ones I have on my PSP...will it brick my PSP? Or will have I have 2.00 CWF again?