Install SentinelROM based on Android 4.2.2 JB for the Samsung Galaxy S3 I9300

Flash SentinelROM Jelly Bean 4.2.2 custom ROM for Samsung Galaxy S3 I9300

Samsung Galaxy S3 can be updated to Android 4.2.2 via SentinelROM 4.60 using this tutorial guide. Make sure to read the entire post and you should be able to complete the install in under 5 minutes without bricking your smartphone. This post contains a custom Jelly Bean 4.2.2 ROM and not an official Samsung / Google OTA Update installation.

SentinelROM is based on Android 4.2.2 Jelly Bean AOSP ROM and it uses the Linaro tools package to improve the overall performance of your smartphone. The main features of this custom ROM are as following: zip aligned ROM, based on AOSP Jelly Bean and CM 10.1, LMT Pie Controls, support for OTA Update from within the phone’s Settings menu, better web browsing performance, improved 3D gaming, better battery life, support for adding themes, UI changes and multiple others.

This custom ROM has been created by Sentinel196, an XDA member and ROM developer. If you want to flash this custom ROM on your Galaxy S3, you will first have to read the preparation guide below so that you will manage to flash all the required files at your first attempt. Make sure to read all the guidelines and continue to the tutorial only when you’re sure that you can complete the installation successfully. Here’s what you need to know:

  • use this post only with Samsung Galaxy S3 International variant with I9300 model number. Don’t try to flash the files you find here on any other Android smartphone or tablet.
  • installing the wrong files on an Android phone will brick its firmware, making it unusable.
  • your smartphone has to be rooted and running a custom Recovery image such as TWRP or CWM.
  • I have used the ClockworkMod – CWM recovery with this post, but you can use TWRP, too. The instructions are very similar and you will be able to complete the installation using TWRP.
  • use the custom Recovery Mode to create a NANDROID backup of your current ROM before starting to install SentinelROM files. Such backup will act as a restore point and you can use it in case the new OS doesn’t want to boot with your SGS3.
  • in the ‘how-to’ guide you will find a step that tells you to wipe data and factory reset your device, which is why you should know that all installed apps, SMS, Call logs and other data stored on it will be deleted. The internal SDcard of your device won’t be affected by this process, but you should still backup some of your most important data files.
  • try to backup your SMS, call logs info and APN Internet Settings using these Android tools: SMS backup & restore | Call Logs backup & restore | APN Settings Backup & Restore. Some of these apps will ask for root access, which is why you have to grant it if you plan to use them.
  • if you intend on backing up data from installed apps, then you should try and go a Google Play Store search for such apps.
  • remember to sync the Contacts info with your default Gmail account. This process will backup all the phone numbers and other Contacts data that’s currently stored on your device.
  • enable the USB Debugging from your phone’s Developer Options.
  • the phone’s battery power levels should be over 50%, so that the phone won’t switch off in the middle of the installation process.
  • this is a tutorial for advanced users who want to tinker with custom ROMs before deciding for a permanent version.
  • note that we cannot be blamed in case you lose any important files nor in case you brick the phone.
  • don’t skip any steps listed below and you should be able to complete installation at your first attempt.

I think that these were all the instructions that you had to go over before moving to the next part of this tutorial.

How to flash SentinelROM 4.60 based on Jelly Bean 4.2.2 for Samsung Galaxy S3 I9300:

  1. Download the SentinelROM zip from HERE or HERE. Save the file on your PC and don’t extract the contents within.
  2. Download Gapps file for Android 4.2.2 custom ROM from HERE. Proceed just like you did in step 1.
  3. Connect your device to your PC and then move both files onto its internal SDcard. Unplug the SGS3 from your computer when the files are copied successfully.
  4. Power off the phone now.
  5. Boot the device into CWM Recovery mode using Volume Up, Home and Power buttons simultaneously.
    > release the buttons when the Galaxy S3 screen flickers and the main custom Recovery Mode menu should load.
  6. Select ‘backup and restore’ and create a NANDROID backup of your currently installed ROM. Return to CWM Recovery main screen when you’re done with the backup.
  7. Select ‘wipe data/ factory reset’ and confirm. Get back to the first menu.
  8. Select ‘install zip from sdcard’ and then you need to select ‘choose zip from sdcard’. Find the SentinelROM zip and confirm that you want to install it.
  9. After the custom ROM is flashed with success, select once again ‘choose zip from sdcard’. Locate the Gapps file. Complete the installation.
  10. After all files have been flashed, you need to select ‘reboot system now’ from CWM Recovery main menu.
  11. Your Galaxy S3 device will now begin the first boot process with SentinelROM. Allow it several minutes to complete the loading of all these new files.
  12. Enter your Google Account details when the home screen appears. That should be the last step you had to take in order to complete the ROM installation.

If the first boot process takes too long to complete, you will need to power off the phone completely. Remove its battery, then re-insert it after 5 seconds have passed. Repeat the entire tutorial once again and make sure that you don’t skip any steps this time. Apply the ‘factory reset’ step again and complete the guide. Custom ROMs such as Sentinel 4.60 might not install at the first step and that is why you have to keep trying until you manage to flash all files.

These were all the steps that you had to take. Test all its features and tell us in comments how is your Galaxy S3 behaving while running SentinelROM 4.60 Jelly Bean 4.2.2 operating system.

In case you don’t like this new OS, then you should use the CWM Recovery mode and restore the NANDROID backup of your previously installed ROM.

For any other questions, use our comments section and we will offer you a solution for any problems that you might’ve stumbled during the updating process.

Samsung Galaxy S3 Articles