How to update Samsung Galaxy S3 with Android 4.2.2 Jellybean ROMI am dividing the complete procedure in 3 parts. I suggest you to read all the three parts simultaneously otherwise you will get nothing. PART I (Pre-Requisites) This is a custom ROM which will void your warranty (however you can easily get it back) + it comes with the lots of risks (even bricking also). So it is advised to secure your device fully before trying anything out. Please follow these pre-requisites and save your device from various kinds of threats. PART II (Downloads and main processes) Download these two files to computer: • Android 4.2.2 Package • GApps Package How to boot to Recovery Mode (required in step III): At first turn OFF your S3. Now press and hold Vol. Up + Menu buttons and while pressing both the buttons press the power button. It will boot you to recovery mode which is required in last part. Please backup your current ROM from recovery mode (you will get options in recovery menu). STEP III (main part) Once you have followed all the pre-requisites and have downloaded the required files on computer, you can step further with this ultimate guide. It will end up you with all new features of Android 4.2.2 on your Galaxy S3.