QUOTE FROM THE ARTICLE
Carriers are using these software locks to force customers to stick with their service. They don’t want subscribers to be able to bring their own devices or re-use the same exact device from another carrier on their own networks.
Carriers are using these software locks to force customers to stick with their service. They don’t want subscribers to be able to bring their own devices or re-use the same exact device from another carrier on their own networks.
Why you can’t take your unlocked iPhone 4S to another U.S. carrier | Mobile - CNET News