Wirelessly posted (iPhone: Mozilla/5.0 (iPhone; U; CPU iPhone OS 2_0 like Mac OS X; en-us) AppleWebKit/525.18.1 (KHTML, like Gecko) Version/3.1.1 Mobile/5A347 Safari/525.20)
I haven't heard of anyone doing this. I wouldn't recommend it. You could brick your phone doing that. The best bet is to upgrade and wait for the release of an unlock procedure for 2.0 and then unlock it. Or if you need to use it on another carrier now, unlock it with a procedure that will allow you to lock it back and then lock it back before upgrading to 2.0.