Mobile phones purchased beginning Saturday can no longer be legally unlocked by U.S. consumers to enable them to work on different networks.

The reason, as we reported three months ago, was that the U.S. Copyright Office is no longer granting unlocking an exemption to the Digital Millennium Copyright Act. The DMCA makes it illegal to “circumvent a technological measure that effectively controls access” to copyrighted material, in this case software embedded in phones that controls carrier access.