Returning to Official Firmware

[Enigma]

Hi, my cousin asked me to try and return his psp Ver 3.03 CFW to official firmware (dont ask me why it's my cousin's psp) and I just couldn't find a way to do it so can anyone help me return the psp to official firmware? I've tried running network update and it shows the dadadada error.
if anyone can help it would be great.

 

[january39]

probably best to get hellcats recovery flasher and go up to M33 and then run the OFW eboot from GAME.

http://downloads.exophase.com/521/hellcats-recovery-flasher-160/