Try taking the battery out and putting it back in, if the psp screen stays blank when you turn it on, the green LED flashes then the system turns off, you have a bricked psp. You will need to take it back to the store and thell them what happened.
The only way I can think of an official update would brick a psp is if the battery power is too low (I thaught updates just wouldnt run if the power was below a certain level however) or he took the battery out during the update.
I'm on firmware 1.5, havnt done a lot of updating myself
