Upgrade Galaxy S3 GT-i9300 with Sotmax Jelly Bean 4.1.2 Custom ROM

Another custom ROM to the rescue! This time, a tool of this kind helps users of Samsung
S3 GT-i9300 get an update to Jelly Bean 4.1.2
. The custom ROM we used to make this possible is Sotmax, but it’s not official firmware.

But even the recently XXDLH8 firmware update or the Flash ROMROW Extreme ROM was never official. However, we are happy to announce that we encountered no problems with the new one.


A successful upgrade is always in need of some pre-requisites. Let us see the ones needed for this procedure. The computer you will employ has to have its security software deactivated and it must run Windows, you are going to need to create backups, the battery has to be fully charged, USB Debugging is required to be turned on, the Galaxy S3 i9300 should be rooted and a wipe has to be done.

Should the warranty of the phone go away, you can regain it by either using the original stock ROM or getting an update from the producer’s website.Galaxy-S3-GT-i9300

Did you read all of the requirements carefully? If so, do the same for the steps included in the tutorial below.

Important instructions

  1. Our guide on how to update your Samsung Galaxy S3 GT-i9300 with Sotmax Jelly Bean 4.1.2 custom ROM starts with step number 1. Which prompts you to , then move the file to the phone’s SD card.
  2. Step number two asks the following from you: switch the handset off. Restart the S3 i9300 into Recovery Mode using the keys for Home, Volume Up and Power. These buttons need to be pressed and held at the same time. Now use the Recovery menu to opt for Factory Reset/Wipe Data.
  3. [sc name=”banner-jos”]For step three do as follows: opt for Wipe Cache Partition (from the same Recovery menu). Choose Go back so that you can easily go back to the phone’s main menu.
  4. Step number four will need you to opt for Install ZIP from SD Card from the Recovery menu too; now select Choose ZIP from SD Card, grab the file you downloaded and flash it.
  5. The next step of our guide is the fifth one; for it to function well you are required to choose Go back.
  6. The final step is this one: opt for phone’s restarting. If this process needs too many minutes to finish, don’t sweat.

At some point or other you may feel like getting the S3 original OS back. Should you have created a full NANDroid backup with the stock ROM, you can get the original operating system of the phone via a simple restart in Recovery Mode.