before you even update you need to do the gen bypass if your try to update it will tell you your on FW9.99 and no need to update
but since you have a fully hackable psp i would myself run 6.60 ME v1.8 its very stable has a built in popsloader for playing PSX games ect ect ect



I found el Guapos help somewhere that lead me to the Ultimate PSP guide so that will help me.