I've noticed on an old iPhone 3G I keep around for testing that the Set Automatically option in Date & Time doesn't work. This iPhone has a SIM card, but it has been deactivated by the carrier after upgrading to a newer model which uses a different size card.
I assumed it would work using Network Time Protocol (NTP), which means it should be able to sync the time over WiFi. But I haven't find any documentation on this.
I keep this iPhone around for testing, so it only comes out of the drawer every few months. Keeping it fully charged isn't a realistic option.
This phone is running the final version available for it, iOS 4.2.1 (8C148).
My question, then: Can I make this work? Failing that, is there documentation available that says once and for all that it can't be made to work?