Update Galaxy S3 I9300 to Jelly Bean 4.3 Avatar Nightly custom ROM

Avatar Nightly Jelly Bean 4.3 based custom ROM is with us again, this time for Samsung’s Galaxy S3 I9300. If you haven’t heard, we already updated Galaxy S2 I9100 with this firmware, so there’s no reason to fear this particular tool. It has brought in many accolades thanks to what it has to offer.

Which is exposed in detail here: many different ways to customize your handset, performance and battery enhancers, custom ROMs which can be flashed on your smartphone if you want to and new features.


On the way to the update steps you will need to stop for a bit and spend some time with these pre-requisites:

  • follow a rooting tutorial for your handset;
  • the Galaxy S3 I9300 must be factory unlocked;
  • install a custom recovery on it from this place;
  • turn on USB Debugging;
  • make a regular and a full NANDroid backup using these the tutorials from here and here;
  • sync your phone’s Contacts with the Gmail account you own using this guide;
  • charge the battery on your handset.Galaxy-S3-GT-i9300

Installation guide

Should you be over with our requirements, the only thing left to do is to update your smartphone. For that, follow the steps we prepared in the paragraphs below.

  1. We advise you to start the guide by downloading the and Gapps from here on your laptop, after which it’s recommended to transfer the two files from there to the handset’s SD card root.
  2. The transfer is going to end successfully only if you first plug the phone to the other device. Once these copy and paste task is done, you can unplug the Galaxy S3 from your laptop.
  3. Then boot the smartphone into Recovery Mode following this guide (for rooted devices) and create the NANDroid backup we told you about (only if you haven’t already made such a backup). But this backup relies on what sort of custom recovery you have. In case it’s TWRP: first tap “Backup” and opt for “Swipe to backup” after you’ve chosen those system parts you wish to see backed up. If CWM is the tool, you should opt for Backup & Restore and after that save, on the external / internal storage of your handset, the backup file.
  4. After you are back in the Recovery screen, you should apply a factory reset. Which also depends on what custom recovery you’re dealing with. If the CWM is your choice, you have to opt for Factory Reset/Wipe Data and then have this confirmed. If, however, you work with the TWRP, you need to tap “Wipe” and choose “Swipe to factory reset“.
  5. What’s left, for now, is to install the update file. Is your handset sporting the TWRP? Then you will have to do this if you wish to flash the right file: tap “Install” and then make sure you confirm the flashing of the said file once you’re near it.
  6. [sc name=”banner-jos”]But what if your phone deals with the CWM instead? You will need to simply opt for Install zip from SD card, select Choose zip from SD card and, after you’ve located the upgrade file, you can confirm its flashing.
  7. The Gapps will appear on your handset, too, once you’ve repeated all the steps that brought the Avatar file on it.
  8. You will have to be back in the Recovery screen for the rebooting of the I9300 into Normal Mode and into the two files.

The NANDroid backup file which we wanted you to create will come in handy if you aren’t a fan of the phone’s new ROM. When your smartphone encounters a boot loop, you will have to redo the whole guide.