Install G920AUCU3BOI2 Stock 5.1.1 Galaxy S6 SM-G920A

Grab the stock G920AUCU3BOI2 for AT&T Galaxy S6 (SM-G920A). This file is for those who may want to restore back their modified or rooted Galaxy S6 SM-G920A to stock G920AUCU3BOI2 Android 5.1.1. Yes, you! This is for you.

The G920AUCU3BOI2 is officially released on September 26,  bumping the device to Android OS version 5.1.1 from Android version 5.0.  The  G920AUCU3BOI2 5.1.1 update also brings several new features such as the Samsung Pay, Android Pay,  UHQ audio, Live video broadcast and some of AT&T’s default apps.

In addition, there is also some significant changes in the user’s interface like the new Apps icon design. Among the rest is an address to improved the device performance, including bug fixes to some issues.

Here ‘s what it reads in Settings > About device (see the screenshot below):
G920AUCU3BOI2

  • Android version: 5.1.1
  • Baseband version: G920AUCU3BO12
  • Kernel version: 3.10.61-5527015
  • Build number: LMY47X.G920AUCU3BO12

Reminder: You’ll never be able to root the G920AUCU3BO12 5.1.1 update. If you’ll flash the O12 you’ll lose root if you have a rooted Galaxy S6 G920A.  Once installed you’ll not be able to go back to previous update that’s simply because the bootloader is locked-up.

Downloads:

  1. Stock G920AUCU3BO12 tarball (Download)
  2. Odin3_v3.10 (grab it here)
  3. A USB Driver if you haven’t installed Smart Switch (grab it here)

Backup your files, recharge the phone, install the USB driver, and extract the downloaded stock firmware

Backup the stored data from your phone as this process will wipe it all. See to it that your phone’s battery should have at-least 50% remaining power. The don’t forget to install the USB driver first to avoid flashing failure. You may also need to extract the downloaded file which is packed in a (zip) so that you’ll get the (tarball) file.

Run and Configure Odin
Run Odin multi-downloader Odin3_v3.10 on your PC desktop. Watch out the check-boxes options on the right top of Odin, ensure that the ‘Phone Bootloader Update’ (only if your device runs on 4.3), ‘AUTO-REBOOT’ and ‘F.RESET TIME’ checkboxes must be checked. Only the ‘RE-PARTITION’ is unchecked.

Reboot the Samsung Galaxy S6 into Download Mode
To reboot the Galaxy S6 into download mode, you need to turn the power off. After it completely shut off, just press and hold the Volume Down key, Home button and the Power ON/OFF button simultaneously.
You should then prompted into a warning screen and asking you to press volume up if you want to continue or volume down to cancel, just simply press volume up to get into download mode. The downloads mode then displays an Android robot and say’s “Downloading.. Do not turn off target!!”

Connect your GS 6 Phone to PC
Once you already reboot the phone in download mode, simply connect the phone to your PC.
In Odin window – the ID:COM box will turn to blue color and indicates the COM port number and a message says “Added” on a log cat box will prompt you that the device is already detected or recognized by Odin. Your COM port number might be different from mine. If you do not see a COM port number then there’s something missing or wrong. You may read again from the top of this post.

Load the stock G920AUCU3BOI2 binary firmware
The stock firmware is packed in a single .tar.md5 file only. Simply click on the AP button, then browse to the folder where the file you have previously extracted and then select and load it.
AP button: “G920AUCU3BOI2_User_HOME.tar.md5″

Start on Flashing the G920AUCU3BOI2 stock firmware
Once if all set and ready to fire-up, hit the “START” button in Odin to begin flashing the stock ROM. Do not ever interrupt the phone while already in flashing progress, like disconnecting the cable or turning off the device. Just wait until it completely finishes.

Wait until you see the PASS!! message
When the Stock Firmware installation successfully completes, you will then see a word “PASS” in Odin. This indicates that the flashing already finishes, and on the log box it says “All threads completed (succeed 1 / failed 0)”. The phone will just then automatically reboot, then it’s about time to remove it from PC or laptop USB connection.