I think it's easy to become trapped into believing that the Volt has WiFi-type connectivity, or mobile wireless. Definitely the Volt does not have WiFi. (Although, how cool would that be?) And I don't think it has a mobile wireless plan because that would be pretty expensive, like $50 per month.
For sure the Volt has a cell phone. In fact there is a real, 10-digit phone number associated with every OnStar vehicle. Furthermore, I'm almost certain that the Volt can send/receive SMS text messages. That's how MyLink seems to communicate with the Volt, and why it takes up to a minute to complete the handshake. Generally SMS is limited to 160 ASCII characters per message.
So...
Downloading a 10K software patch to the Volt at a rate 160 SMS characters every minute or so would be tedious at best. Even with MMS (bigger pipe) it would not be practical.
My guess is that the Volt is eminently upgradeable--at the dealer, with a hard wire.
Please prove me wrong. I want to go crazy thinking of new aps for the Volt using a big wireless pipe!!!
Chris