Update Galaxy S3 SGH-SCL21 to Android 4.1.2 KDBMK1 Official Firmware

Galaxy S3 SGH-SCL21 is just the right smartphone for what we want to teach you today. And that is: how to update your device to Android 4.1.2 with official firmware.

This official firmware was launched last month for Japan (AU KDDI carrier) and it’s called KDBMK1. Your Galaxy S3 SCL21 was launched in May 2012 and it’s the only model that works with this guide; you will only brick your device if it’s not the model we mentioned.

The KIES logo of the new firmware is activated, which
lets you upgrade your phone by Samsung KIES as well
. Also, you can opt for OTA (over the air) method via the Software Update button located under Settings menu in case you don’t want to follow our tutorial. But you should, since we try and explain everything in a simple way so that not only pros can update the phone, but newbies as well.

As for the kind of goodies the Jelly Bean 4.1.2 comes with, here they are: extended sync timing, triple buffering, a fixed frame rate of 60 fps, touch anticipation, Google Now, mini apps and so much more. Should your SCL21 be rooted, the new firmware will affect it by deleting the phone’s system partition and revoking the root access. The important data on your handset will not be erased; the internal and external SD cards will also remain intact.


Every guide should have the following pre-requisites to help with the update:

  • enable USB Debugging;
  • open the security programs running on the phone and laptop, then turn them off until you’re done with the tutorial;
  • create a standard backup and a NANDroid one, using these tips;
  • make sure the handset has it’s battery fully charged;
  • your laptop must have Windows as the operating system;
  • flash USB drivers compatible with your smartphone model from this page on your notebook.Galaxy-S3-SGH-SCL21


Below you will find all the steps that you must follow to go through a smooth upgrade.

  1. Download Odin tool from here and on the laptop or personal computer you own, then be sure to do this: extract the packages in the same place and then have your phone boot into Download Mode by pressing and holding Volume Down, Home and Power simultaneously until you see the device come up with a warning message.
  2. Once your handset is in the necessary mode, you have to go to Odin. Open the latter as an Administrator and after that connect, with the handset’s very own USB cable, the Galaxy S3 SCL21 to the laptop; if you aren’t welcomed by an “Added!!” message and an ID:COM box with a yellow color, you have to try to establish the connection by opting for one of these methods: search for another USB port to use or flash, again, the USB drivers.
  3. Next task that needs your attention is made up of the following instructions: once you are done tapping PDA you should opt for a file that has a CODE in the name, then click on Phone, choose a file which should have a MODEM in the name, be sure to continue by clicking CSC and then making sure to choose a file with CSC in the name, click on PIT and opt for a file with a .pit extension.
  4. You will come across a group of boxes; out of them, activate only the ones which have F. Reset Time, Auto Reboot and Re-partition on them. Then do this: tap, as soon as you see it, the button called “Start“.
  5. [sc name=”banner-jos”]Prepare to experience the flashing of the new firmware on your handset in the next minutes. After this file is on your device, the latter is going to restart; wait for that, then wait some more until the display has “Pass” on it. This is your cue to do the following: unplug the phone from your laptop.

The Android 4.1.2 KDBMK1 is officially installed on your Galaxy S3 SGH-SCL21 and you can launch it from your device’s About Phone (which will open after you tap Settings). And that’s it: you now have an updated smartphone to play with!

In case you don’t see what’s so great about this new tool, you can have the previous ROM restored. How? By using the NANDroid backup will that will revoke the update. If you encounter problems during the upgrade, leave them in the comment field below.