my psp has custom firmware 5.00 M33-4 Slim, my friend came to my house and he had the official firmware not hacked and without knowing i took his memory card and put it into my psp and it could not read it,,,i restarted it,but nothing happened ,,so i took MY memory card back and put it into my psp and it waz not able to READ MY MEMORY CARD!,,i restarted it but nothing happened!!,i connected it to the PC and it was saying ""Insert Memory Card"",,please help ,,if i have to reinstall custom firmware please tell me how...ohh and,,
my memory card waz working in my friends psp!!!

so to sum up my psp wont read any memory cards!!and i think formatting the memory card wont help,,i was thinking to upgrade my psp to official firmware and then hack it back to custom firmware but will it upgrade if it does not have a memory card????
PLEASE HELP