Is a genuine PSP Phat 5.03 flashable?

I have a PSP phat. firmware 5.03.

Is this flashable with a Pandora battery.

When i try and run the file it says the files are corrupt. But i tried it in my other PSP that is already flashed and it started to boot up the program.

I think i need a 100% upgrade to then allow me to run the other updates.

Any idea?

Thanks guys.

 

You dont need a Pandora Battery, go here

http://forums.afterdawn.com/thread_view.cfm/774384