This is absolutely a very big help that we can find Android 4.2.1 custom ROM for all of the top three leading mobile phone operators. Currently Samsung Galaxy S3 can be updated to Official Android 4.1.2 which is behind Android 4.2.1. In case you want to go for 4.2.1 then you can use this custom ROM. Thanks to Cyanogenmod 10.1, we have three separated custom ROMs for each operator so you will be able to enjoy the best part of the update.
Please note that this custom ROM doesn’t have Google Apps so you need to manually install it. However the process is very simple that you can read the rest of the article to find the download links as well as how to install it on the phone.
- This guide and tool only with Samsung Galaxy S3 so do not attempt to use with other Android phone since it can damage the device
- Backup everything you want before starting
- Check out your phone batter make sure it has more than 70%+ to make sure that it won’t run out
- Disable any antivirus since it might block the process
- We do not responsible for any loses or damage. Do it at your own risk.
How to Backup Samsung Galaxy S3
How to Update Samsung Galaxy S3 to Android 4.2.1
Step 1: Enable USB debugging option on your phone by going to “Setting” > “Applications” > “Development” > check on the box there to enable “USB Debugging”.
Step 2: Now connect your phone to PC via USB cable then copy the Android 4.2.1 and Google Apps (downloaded above) to SD card.
Step 3: Turn off the phone and boot into Recovery Mode by pressing “Up Volume”, “Home Button” and “Power Button” at the same time. Release them when the screen is on.
Step 4: Now on Recovery Mode, use the up and down volume buttons to wipe all data. Then select, “flash zip from SD card” and press power button.
Step 5: Now navigate to where you stored Android 4.2.1 custom ROM in step 2. Now select the zip file then press power button to confirm the installation.
Step 6: Repeat what you have done with Google App to install it.
Step 7: It will take a few minute for the installation. After completed, select “+++++Go Back” then “reboot system now” to reboot your device. This is the first reboot so it might take longer than use about 5 minutes.
Good luck! Now your Samsung Galaxy S3 is running on Android 4.2.1. Enjoy the new features. If you encounter problem, please read the whole steps again.