If you are looking for one-stop, do-it-all Android 5.1.1 custom ROM for your AT&T Galaxy S2 SGH-i777, definitely check out the latest SlimLP ROM.
Based on the latest Android 5.1.1, SlimLP ROM is the Lollipop sibling of its original Slim ROMs. And if you guys have been following GalaxyS2Root.com for the last few years, you probably remember that Slim ROMs started with the SGH-i777 (yes! This is where it ALL STARTED!).
Now, SlimLP ROM is available for many other/newer Android devices and it’s one of the lightest/fastest AOSP ROMs (What is AOSP?) in the custom ROMing world.
The SlimLP ROM comes with its own SlimLauncher (just as good as Trebuchet or maybe better?) and a few customization for your status bar, recents, navigation bar, and some more. This isn’t the most customizable ROM in the world but then again, I find this ROM more stable (no random reboots) than any other Android 5.1.1 custom ROM I’ve tried so far on the SGH-i777.