Android 6.0 Marshmallow is just around the corner and with it comes the hope of better battery management among other performance improvements and under the hood optimizations. However, until that happens, we would have to rely on Android 5.1.1 Lollipop. The list of Android 5.1.1 custom ROMs has taken longer to build up and is now finally starting to see some popular names and stable custom firmware. Adding to this list is AOSP Android 5.1.1 Lollipop custom ROM.

AOSP is one of the most popular custom firmwares loved for it isthe closest to the stock Android look and feel. Bringing stability and improved performance, you can now flash AOSP Android 5.1.1 Lollipop on your Samsung Galaxy S3 I9300. As with all the custom ROMs, this too is not an official release by Samsung, but just acustom ROMwhich would require acustom recovery like ClockworkModto flashthe ROMzip fileon your phone. Follow this guide to flash AOSP Android 5.1.1 Lollipop your Galaxy S3.

Prerequisites to installAOSP Android 5.1.1 Lollipop onGalaxy S3:

Create abackupof all important data in your Galaxy device.

Download and install USB drivers forSamsung Galaxy S3in your computer.Enable USB debugging option by pressingMenu>Settings>Applications. Navigate and tap onDeveloper Optionsto ensure thatUSB Debuggingis enabled.Make sure that recovery tool likeClockworkMod recoveryis installed.Ensure that your Samsung Galaxy S3 i9300 carries more than 80% of charge.

How to install AOSPAndroid 5.1.1 Lollipop on Samsung Galaxy S3:

Files required:downloadAOSPAndroid 5.1.1 Lollipopcustom ROM; also downloadGoogle Apps. Save both files on PC.

Here are the steps to updateGalaxy S3 i9300to AOSP Android 5.1.1 Lollipopcustom ROM:

Connect your SamsungGalaxy S3 I9300to your computer using USB cable and copy the downloaded files to the SD card of your Galaxy device.Disconnect the connection with PC and turn your GalaxyS3 off.Boot into custom recovery mode: press and holdVolume Up, Downand thePowerbuttons simultaneously untilSamsunglogo shows up. Leave the keys for half a second and hold again. UseVolumekeys to scroll andPowerbutton to select -alternatively you can useQuick Boot appto reboot your Android device in recovery mode.Now perform Nandroid backup of your current ROM: selectBackup and Restore>Backup. Go back to main recovery menu after backup process is done -very important step to restore back to current OS.Data wiping tasks: selectwipe data/factory reset>Yes. It will take a few minutes; once done, selectwipe cache partition.Next tap onAdvance>wipe Dalvik Cacheto wipe Dalvik cache data too.Selectinstall zip from sdcardfollowed bychoosezip from sdcard. Locate the Android 5.1.1 based custom ROMfile copied earlier and select it. Tap onyesto confirm installation and wait for the ROM installation to be completed.Once installation process is finished successfully, repeat the above step, but chooseGAppsfile instead to install the Google apps package on your SGS3 I9300.Return to main recovery menu now and selectreboot system nowto boot up into the latest Android 5.1.1 Lollipop custom firmwareforSamsung GalaxyS3. It will take a bit of time during the first boot, so kindly be patient.Ta da! Enjoy Lollipop on Galaxy S3.

How to restore:If you want to return to previous OS on your SGS3, boot intorecovery, selectbackup and restorethen restore your previous ROM by selecting it from the list.