If you're going to sell it, I wouldn't touch the software update mechanism at this point and maybe let the new buyer decide if they want it or not. there's no benefit to you to perform the update that I am aware of.
You do know that even discussing ways to "hack" a Device in order to defeat a feature put in place because of a federal law aint exactly kosher ( meaning its illegal ).
If we were to give you this info and you went out and did something stupid...