How to un-disable an iPhone 4?

I have already restored it numerous times and it still tells me to connect it to iTunes.
It is my friends old iPhone which she forgot the code to and now has been disabled.
Restoring it hasn't worked, and I don't know what else to do…
Help me please.

Did you try unlocking it using an application like redsn0w? If not, give it a try. If that doesnt work, did you select (Start as new iPhone) or (Use Back-Up)? If you restored it from the backup, then the password will always be there. Theres no way to get through, if there was a way, there'd be no point in having one in the first place.