Unhack PSP with Firmware 6.60 pro b9

I’m trying to unhack my PSP2001 because I want to trade it in to Gamestop but I think it would be best to not give them a hacked PSP haha. Any information would be helpful. Thanks
Answer #1
I think you just have to download the latest OFC and install it on the psp if you have installed the CFW on your memory stick. Grab it on the official Sony website http://us.playstation.com/support/systemupdates/psp/index.htm
Answer #2
Normally if you install a newer original game(borrow or rent one) it will ask if you wish to update the firmware, thus installing official firmware. (my son is always doing this, so I have to keep re-hacking it).
Answer #3
Is it really that easy? Thanks I’ll give it a try when I get home to my computer (on my phone right now)
Answer #4
I just went to the Playstation website and downloaded the latest update and tried to install it but it told me my PSP is already up to date.