Network locks are a way for carriers to ensure subscribers finish up with their contracts (networks can easily block the IMEI of handsets that belong to delinquent accounts). However, having your phone opened to other networks does have its benefits. For example, if you’re traveling abroad, you can avoid hefty roaming charges by buying prepaid SIM cards.
Samsung’s flagship Galaxy S3 is usually released in the U.S. on-contract, which means it will be locked to your carrier. While some carriers will allow network unlocking for a charge, enthusiasts would usually be able to do an unlock through free means. On the XDA Developers forum, user zohawkish released a free unlocking tool that would render your Galaxy S3 “open line.”
As of this writing, though, the original post had been pulled down. Zohawkish pulled out support for the unlock tool given complications that have arisen, particularly with the need to backup EFS and restore the backed-up EFS if a user wants to update to future Jelly Bean releases.
In short, is it worth the trouble to unlock your phone at this point?
A comment-poster on the XDA Developers blog said the method will change the phone’s IMEI. Uh oh! But don’t fret. Yet another commenter has pointed to an alternative solution, which unlocks the Galaxy S3 in safer manner through a the GalaxSim Unlock app.