http://blog.caranddriver.com/can-you-unlock-gms-4g-lte-and-use-mobile-carriers-besides-att/
I too was lured by the headline. The key statement is: "Currently, the 4G LTE service is bundled with OnStar, and it’s a connection that runs deeper than marketing. AT&T provides the connection for OnStar service, in addition to a simple data connection for the onboard Wi-Fi hotspot, meaning incorporating other carriers requires plenty of compatibility testing to ensure OnStar service isn’t affected."
My conclusion is that we will always be tied to AT&T for 4G LTE access in the Spark EV.
I too was lured by the headline. The key statement is: "Currently, the 4G LTE service is bundled with OnStar, and it’s a connection that runs deeper than marketing. AT&T provides the connection for OnStar service, in addition to a simple data connection for the onboard Wi-Fi hotspot, meaning incorporating other carriers requires plenty of compatibility testing to ensure OnStar service isn’t affected."
My conclusion is that we will always be tied to AT&T for 4G LTE access in the Spark EV.