I have 3.0 on my iPhone 3G with a mobileconfig enabling tethering. Whenever I turn tethering on, I lose visual voicemail until I reset network settings - not really a big deal. Obviously, the 5.5 Carrier Update disables this method of tethering, but is it possible to use the old tethering/MMS ipcc that was released a while back? And if I did that, would I consistently lose voicemail (because MMS is always active, while tethering is only on every now and then)?