You can update Galaxy S3 i9300 to Android 4.4.2 KitKat using theRevolutionary S5 custom ROMwhich is based on stock Android 4.4.2. Revolutionary S5 carries a lot of resemblance to Samsung Galaxy S5 firmware as it has been modified to match the TouchWiz of latest Samsung flagship.

-Some of the best Android Lollipop Custom ROMs

Revolutionary S5 Android 4.4.2 KitKat features:

Updater SU 1.93build from Ricky310711 rom kitchenpatched updater-script for ANY recovery4.4.2 statusbarS5 accuweather themedDebloated to the maxRam free average 360MBfixed livewallpaper picker bugincluded sunbeam LWP(to avoid crashes)fixed livewallpaper installation from bloatNew hosts file provider(3x the size of MoaAB)Fixed R95QuickConfigTweaksBetter ram managementadded multi dpi supportoptionto install260 dpioptionto install290 dpioptionto install320 dpiaromainstallernew aroma splash screenNew grid sizedFixed accuweather bugadded choice of wipes-system(auto)-data-cache-preload-sdcardAdded choice of backups-downloaded apps-efs-recovery settingsSamsung tool to aromaadded odexing to aromaadded aggression to aromaadded supercharger to aromaadded xrealty to aromaadded crossbreeder to aromaadded disable bootanimation to aromaadded disable bootsounds to aromaFixed launcheradded note 2Settings more themedNC Toggle color fixesAdded leaked update of playstoreNewest N3 MyFiles2 More new S5 wallpapersChanged default lockscreen wallpaperNote 3 ripple effect libImproved ripple renderingALL Official S5 wallpapersNew over the horizon tonechanged default tone(new over the horizon)S5 themed keyboardadded xposedadded per-app settingsadded wanam xposedpatched app backup scriptfixed datawipe issue from previous versionsnew aroma wallpapernew splash screen

Prerequisites toupdate Galaxy S3i9300 to Android 4.4.2:

Create a backup of 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 like ClockworkMod recovery is installed.Ensure that your Samsung Galaxy S3 i9300 carries more than 80% of charge.

Guide to update Galaxy S3 i9300 to Android 4.4.2 Revolutionary S5 ROM:

Files required:download the Revolutionary S5custom firmware from here; also download theGoogle Apps. Save both files on PC.

Here are the steps to update Galaxy S3 i9300 to Android 4.4.2 KitKatRevolutionary S5custom firmware:

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 in to custom recovery mode: press and holdVolume Up, Downand thePowerbuttons simultaneously until Samsung logo 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 4.4.2 KitKat based Revolutionary S5custom 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 Revolutionary S5 custom firmwareforSamsung GalaxyS3. It will take a bit of time during the first boot, so kindly be patient.Ta da! This was how to update Galaxy S3 i9300 to Android 4.4.2 KitKat based Revolutionary S5!

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.