Any way to remove and iPhone 3G jailbreak without restoring?

[asdf]

Well, I was jailbreaking someone's iPhone and I tell them that they have to rehack it if it turns off. She agrees and I hack it. So then about halfway through, she tells me she wants it off because it will be annoying to rehack it. Before I tell her she can't take if off without restoring, is there any way to do it without restoring?

 

[Raiser]

As far as I'm concerned, no.

The only way that I'm aware of is to restore via iTunes.

 

[Snorlax]

Can't you just upgrade the firmware? Unless, you already have the latest. o_o