you should try this:
1. make sure that the psp's memory card is in (so it can read the Flash files needed), you need the official firmware update, format your memory card and from your computer download the firmware that you try to update on your memory card root
2. make sure psp has been charged and fully turned off (psp 3000 users remove battery and use AC adapter)
3. hold down the following... START, SELECT, SQUARE and TRIANGLE (all at the same time) and turn psp on remember to continue holding the buttons down while it turns on.
4.wait till the psp turns off (semi bricked ones will turn off just like fully bricked incase you get scared)
5. once psp is turned off by its self... turn it on normally and you will have psp set up menu it will take a bit longer for it to turn on (just like if you bought it brand new) and just set it up..
6. not done yet... download your psp's current frimware and re install it...
7 befoure installing your frimware... go to the cfw's recovery menu and disable all plugins and gameboot and cintro's then proceed to install the frimware after frimware installation is complete your done
8. psp working perfectly job is done , if don't it is totally bricked or you should try again an again