With the release of iOS 4.2.1, Apple has again gained the upper hand in the ongoing cat and mouse battle against iPhone unlockers. While the U.S. Library of Congress has decreed that users who choose to unlock their mobile devices for use on alternative networks cannot be prosecuted under the Digital Millennium Copyright Act (DMCA), there was unfortunately no prohibition on companies locking phones in the first place.
As a result, Apple has continued to tweak its locking mechanisms with every new release of iOS, including the one released earlier this week. Starting with iOS 4.2.1, the main part of
