Magic Memory stick help?

I already have the pandora battery it is from a phat psp. i am trying to get a magic memory stick that will work on a slim. it works on my phat.idk why it will not work on the slim. but no lights but the green one turn on. i have even tried the time machine option. the slim is a 4.01 ofw. my phat is 5.01 cfw. please anyone help me