Help psp custom firmware users i broke my magic stick!?

Hi well after a visit into another country my cousins dog a beagle decided to munch on my psp stick while it was on the computer desk. I bought the pandora kit so luckily i still have my pandora battery. now i arrived back into the U.S and i decided to buy this new game mhfu but i needed to upgrade my firmware to play it. I had custom firmware installed and it unistalled it. I have an 8gb memory stick. but even if i use it the same way as the magic memory i used before it wont turn on into the menu screen were i can install my cfw. So i need a way inwhich i can turn this 8gb into a magic memory stick. i heard 8gb could be converted recently but along time ago they couldnt. Im basically an amatuer hacker i know how to do things but when everything goes wrong im screwed please help me.