Upgrading or downgrading your PSP firmware is like you "format" your PSP because every setting in your PSP will be set back to default including your Flash and WMA playback which means you must need an internet connection to activate back all the playback function. For those who can't hardly find an internet connection, there is an option to enable it offline. Just follow this step after the jump...

First, switch off your PSP and make sure it is not in standby mode. Then turn on your PSP and simultaneously press the R button. Then a "Recovey Manu" will appear. In that menu, choose "Registry Hacks" by pressing X button.  Next, go to the "Activate WMA" option and press X, also do the same step on the "Activate Flash Player". Now your WMA and Flash player is activated! To exit the screen, go to "Back" and "Exit". Please note that this step will only work in customize firmware. To download customize firmware, please click here.