AT&T has begun rolling out the Android 4.1.2 Jelly Bean update to select users with the LG Optimus G, almost three months after it was released by LG. The 345MB update, which comes with the JZO54K build number, will be available to download over-the-air.

This is the first Jelly Bean update for the Optimus G, so users will get to enjoy new features like Google Now and Project Butter for the first time. Those who have already downloaded it have been posting their first impressions on the XDA Developers forum, and they report that there are significant performance improvements after updating.

“I have to say I’m noticing a nice difference from ICS to JB in smoothness,” one user wrote. “I was skeptical about Project Butter on such a powerful device, but I’m very happy with the performance improvements.”

AT&T hasn’t made the release official just yet, but as you can see from the screenshots above, it’s certainly on its way. If you haven’t already had your update notification, you should receive it in the coming days. You can also check for the update manually by visiting the system updates menu within your Settings app.

• SourceXDA Developers
• ViaTechnoBuffalo