[Samsung Galaxy S8 Guides, News, & Discussion] Mike15678:
Hello. This is my first guide, so please forgive me if it looks a bit weird. But without further ado I present you with the [Snapdragon] Guide for Flashing Standard Firmware, Carrier Switching, and Flashing Unlocked Firmware for the S8.

Here are some useful reminders:

All download links are at the bottom of this post.

Make sure you follow the "Prerequisites For Anything You decide To Do In This Guide" section.

Don't copy quotation marks, unless I tell you to in this guide.

You will need a Windows computer in order to utilize the software provided. Mac users can use Boot Camp to dual boot their machines. Using WINE is not recommended.

This is an S8 guide, not an S8+ guide. Go to https://xdaforums.com/galaxy-s8+/how-to/snap-guide-flashing-standard-fw-carrier-t3627255 to check out my S8+ guide.

WARNING: Anything you do in this guide will erase your phone completely. It's recommended that you back up before you do anything and that you remove your google account from your phone (so you don't have to go through FRP).

Note: Flashing to stock from Unlocked firmware requires you to follow the "Carrier Switching" section (which eventually requires you to follow the "Flashing Standard Firmware" section) and do as it says, unless the CSC code of your carrier is currently active. You can check this by going into Recovery Mode by holding the Power button, Bixby button, and Volume Up button until you see a dark blue screen with text saying that the firmware is being updated (it's not actually). Once it transitions to a black screen, your active CSC will be on the bottom log (three characters). If your CSC code is already your carrier's, then just follow the "Flashing Standard Firmware section. But for anything you decide to do, you must follow the "Prerequisites for anything you decide to do in this guide" section.

Disclaimer:

I am NOT responsible for any damage done to your device if you decide to use this guide.

Prerequisites for anything you decide to do in this guide (Required):

Standard Odin

Samsung Drivers

Steps:

1) Uninstall Samsung Switch and/or Samsung Kies, if present on your computer. This helps removes any conflicts with Odin.

2) Extract the Samsung Driver zip and the Odin zip to somewhere safe on your computer.

3) Double click on the extracted "SAMSUNG_USB_Driver_for_Mobile_Phones" executable (SAMSUNG_USB_Driver_for_Mobile_Phones.exe) and complete the installation wizard.

3) Navigate to your extracted Odin folder and double click on the Odin configuration file (Odin3.ini).

4) You should have entered Notepad (or your preferred note editor). Find the "[ButtonOption]" section.

5) There should be a setting there called "UMS/PATCH". Change the value of "0" to "1" so it becomes "UMS/PATCH=1".

6) Press the "Ctrl" key and "S" key on your keyboard to save the file.

7) Go ahead and close out of Notepad.

All About Bootloaders (Required Reading):

As Wikipedia puts it, “A boot loader is a computer program that loads an operating system or some other system software for the computer after completion of the power-on self-tests.” In other words, a bootloader is what loads you operating system. In most Samsung phones (including the S8 and S8+), there’s an e-fuse that prevents downgrading of the bootloader. This means any firmware or firmware update containing a lower Bootloader version than the one you have, will FAIL to be applied. There is really no way to circumvent this.

(From what I can tell) S8 firmware released since December are Bootloader v2, while anything before that month is Bootloader v1. In the next section, I’ll be explaining how to properly identify your current Bootloader version.

How to identify Bootloader version:

Steps:

1) Open “Settings” on your phone.

2) Scroll down to “About Phone”.

3a) If you are on a standard, carrier firmware, under “Baseband version” you should see something similar to this: “G950UXXXXXXXX”.

3b) If you are on an unlocked firmware, under “Baseband version” you should see something similar to this: “G950U1XXXXXXXX”.

4) No matter which firmware you're on, the fourth “X” would be either a “1” or a “2”, which means you will have either Bootloader version 1 or Bootloader version 2, respectively.

Note: As stated in the last section attempting to flash firmware that contains Bootloader v1 onto a phone that already has Bootloader v2, will fail. You can update a phone on Bootloader v1 to a firmware that has Bootloader v2, however.

How To Download Firmware with Updato:

Note: This is an add-on section for any part of the guide that requires you to download specific firmware.

Updato can download old or new firmware for phones, therefore you can download Bootloader v1 or Bootloader v2 firmware. However, Updato tends to be much slower than SamFirm, therefore its recommended that you use SamFirm if you’re willing to download Bootloader v2 firmware. You should only use Updato if you need to download Bootloader v1 firmware.

Steps:

1) Go to http://fw.updato.com

2) Type in your Model Number (SM-G950U for carrier S8’s; Firmware for unlocked S8’s can be found in the “Downloads” section)

3) Find firmware for your specific region.

Here are some common Region codes:

BST Boost

VZW Verizon

ATT ATT

USC US Cellular

ACG C Spire

TMK MetroPCS

VMU Virgin Mobile

TFN Tracfone

XAS Sprint

TMB T-Mobile

XAA Unlocked US

SPR Sprint

CCT Xfinity Mobile

AIO Cricket

4) Download it somewhere safe onto your computer.

How To Download Firmware with SamFirm (Faster):

Note: This is an add-on section for any part of the guide that requires you to download specific firmware.

SamFirm can only download the latest firmware for phones, therefore you’ll be downloading a Bootloader v2 firmware. SamFirm tends to be much faster than Updato for downloading firmware, since the firmware is downloaded directly from Samsung.

Prerequisites:

SamFirm (SamFirm_v0.3.6.zip):https://xdaforums.com/galaxy-tab-s/general/tool-samfirm-samsung-firmware-t2988647

Steps:

1) Download “SamFirm_v0.3.6.zip”. Make sure you’ve installed all of its prerequisites listed on the page, such as “.NET Framework 3.5”, “Microsoft Visual C++ 2008 Redistributable Package (x86)”, and “Microsoft Visual C++ 2010 Redistributable Package (x86)”

2) Extract “SamFirm_v0.3.6.zip” somewhere safe onto your computer.

3) Double-click on “SamFirm.exe” to open it.

4) Enter your Model Number and 3-character Region code.

Here are some common Region codes:

BST Boost

VZW Verizon

ATT ATT

USC US Cellular

ACG C Spire

TMK MetroPCS

VMU Virgin Mobile

TFN Tracfone

XAS Sprint

TMB T-Mobile

XAA Unlocked US

SPR Sprint

CCT Xfinity Mobile

AIO Cricket

5) Make sure you’ve ticked the “Manual” checkbox.

6) Input your “PDA”, “CSC”, and “Phone” strings into their respective slots based off the information found from fw.updato.com for your latest specific firmware. Please note that the “CSC” slot is not the same as the same as the “Region” slot; the “CSC” slot should have a long string inputted.

7) Tick the “Binary Nature” checkbox.

8) Click the “Check Update” box.

9) Your firmware should now appear. Make sure the “Check CRC32” and “Decrypt Automatically” checkboxes are ticked.

10) Click on the “Download” box, choose where you want to store the firmware, and relax for a while.

Flashing Standard Firmware:

Prerequisites:

What's listed in the "Prerequisites For Anything You Decide To Do In This Guide" section.

Firmware you want to flash; follow the “How To Download Firmware with SamFirm” or “How To Download Firmware with Updato” section, if you need firmware.

Steps:

1) Extract your downloaded firmware to somewhere safe on your computer.

2) Turn off your S8.

3) Once off, hold the Power button, Volume Down button, and the Bixby button until you see a blue screen on your phone.

4) Press the Volume Up key to enter Download Mode.

5) On your computer, navigate to your extracted Odin folder.

6) Double click on the "Odin3 v3.12.7" executable (Odin3 v3.12.7.exe)

7) Connect your phone to your computer with your USB cable.

8) You should see Odin output "Added!!" in the "Log" tab and underneath the "ID:COM" section, you should see an empty box turn blue.

9) Now it's time to add your firmware files that were extracted earlier. Individually add an appropriate firmware file for each box on the right. The "BL" box will require a firmware file that starts with "BL", the "AP" box will require a firmware file that starts with "AP", the "CP" box will require a firmware file that starts with "CP", the "CSC" box will require a firmware file that starts with "CSC" (DO NOT USE THE "HOME_CSC" file for the "CSC" box), the "UMS" box will require a firmware file that starts with "USERDATA". The "AP" and "USERDATA" files will take the longest for Odin to load because of their size.

10) Go to the "Options" tab and make sure that only the "Auto Reboot" and "F. Reset Time" checkboxes are ticked.

11) Go back to the "Log" tab.

12) Click the "Start" button on bottom right.

13) Sit back and relax for a while. Odin will output what is being flashed in the "Log" and on a box in the top left.

14) The box in the top left will become green and in black letters say "PASS" once the flash was successful.

15) Once the flash finished, disconnect your phone from your computer.

16) Your phone will do an erase at this point, so don't mess with your phone until you reach the setup screen.

17) PROFIT. Follow the setup on your phone and you're good to go.

Carrier Switching:

NOTE: Doing this process does NOT unlock your phone for use on other carriers.

Prerequisites:

What's listed in the "Prerequisites for anything you decide to do in this guide" section.

S8 Factory Binary (either Bootloader v1 or Bootloader v2)

Prince Comsy version of Odin

Google Platform-Tools (ADB)

Canadian HOME_CSC (either Bootloader v1 or Bootloader v2)

Steps:

1) Extract the downloaded S8 Factory Binary, the Prince Comsy version of Odin, Platform-Tools, and the Canadian firmware, to somewhere safe on your computer.

2) Turn off your S8.

3) Once off, hold the Power button, Volume Down button, and the Bixby button until you see a blue screen on your phone.

4) Press the Volume Up key to enter Download Mode.

5) Navigate to the extracted Odin (NOT PRINCE COMSY) folder.

6) Double click on the "Odin3 v3.12.7" executable (Odin3 v3.12.7.exe).

7) Connect your phone to your computer with your USB cable.

8) You should see Odin output "Added!!" in the "Log" tab and underneath the "ID:COM" section, you should see an empty box turn blue.

9) Click on the "AP" box and navigate to the extracted Factory Binary folder. Double click on the file the starts with "COMBINATION".

10) Wait for Odin to load the file.

11) Go to the "Options" tab and make sure that only "Auto Reboot" and "F. Reset Time" checkboxes are ticked.

12) Go back to the "Log" tab.

13) Click the "Start" button on bottom right.

14) Odin will output what is being flashed in the "Log" and on a box in the top left.

15) The box in the top left will become green and in black letters say "PASS" once the flash was successful.

16) Leave your phone connected and let your it reboot into the 'factory binary homescreen' (Basically, the equivalent of a home screen on a regular S8).

17) Navigate to the "platform-tools-latest-windows" folder. Once you’ve navigated to where “adb.exe” is located, click the address bar on the top and press “Ctr+C”.

18) Open cmd.exe through “Run” (Windows key + R)

19) Type in “cd /d “<copied folder location>”” (Make sure you’re putting the folder location in quotes and not the command itself)

20) Type in "adb reboot bootloader". Leave ADB open.

21) Your phone will reboot into Download Mode. Your device should still be connected and ADB should also still be open.

22) Navigate to the Prince Comsy version of Odin and double click on the "Odin PrinceComsy" executable (Odin PrinceComsy.exe).

23) You should see the Prince Comsy version of Odin output "Added!!" in the "Log" tab and underneath the "ID:COM" section, you should see an empty box turn blue.

24) Click the "CSC" box and navigate to the “HOME_CSC” file you downloaded.

25) Double click on the file that starts with "HOME_CSC" (DO NOT USE the "CSC" file for the "CSC" box). It should load quickly.

26) Go to the "Options" tab and make sure that only "Auto Reboot" and "F. Reset Time" are ticked.

27) Go back to the "Log" tab.

28) Click the "Start" button on bottom right.

29) Odin will output what is being flashed in the "Log" and on a box in the top left.

30) The box in the top left will become green and in black letters say "PASS" once the flash was successful.

31) Once your phone reboots, you will see an "IME" button on the 'factory binary homescreen (It’s on the bottom). Tap on it.

32) A number pad should appear. Type in "*#243203855#".

33) A menu will pop up. Scroll down until you find an "XAC" option. Tap on it and tap "Install".

34) Your phone will reboot. Once it reaches the 'factory binary homescreen', go to ADB on your computer and type in "adb shell".

35) *LOOK A TINY BIT BELOW!* Type in "echo "XXX" > /efs/imei/mps_code.dat" (the quotation marks that surround the X's are used, but not the ones that surround the whole command... you know that by now- right?) and REPLACE XXX with your preferred CSC code.

Choose one of these CSC codes:

BST Boost

VZW Verizon

ATT ATT

USC US Cellular

ACG C Spire

TMK MetroPCS

VMU Virgin Mobile

TFN Tracfone

XAS Sprint

TMB T-Mobile

XAA Unlocked US

SPR Sprint

CCT Xfinity Mobile

AIO Cricket

36) Type in "exit" in the ADB shell.

37) Type in "adb reboot bootloader" and flash your desired firmware by following the "Flashing Standard Firmware" section of this guide or by following the "Flashing Unlocked Firmware" section of this guide. PROFIT FOR NOW.

Flashing Unlocked Firmware:

NOTE: The unlocked firmware does NOT unlock your phone for use on other carriers, it only removes bloatware. Some carrier specific features, such as Wi-Fi Calling and VOLTE will not work with the Unlocked Firmware.

Prerequisites: What's listed in the "Prerequisites for anything you decide to do in this guide" section

Prince Comsy version of Odin

Unlocked Firmware (either Bootloader v1 or Bootloader v2)

Steps:

1) Extract the Prince Comsy version of Odin and the Unlocked Firmware you downloaded from below.

2) Turn off your S8.

3) Once off, hold the Power button, Volume Down button, and the Bixby button until you see a blue screen on your phone.

4) Press the Volume Up key to enter Download Mode.

5) On your PC, navigate to your extracted Prince Comsy Odin folder.

6) Double click on the "Odin PrinceComsy" executable (Odin PrinceComsy.exe).

7) Connect your phone to your PC with your USB cable.

8) You should see PrinceComsy's Odin output "Added!!" in the "Log" tab and underneath the "ID:COM" section, you should see an empty box turn blue.

9) Now it's time to add your firmware files that were extracted earlier. Individually add an appropriate firmware file for each box on the right. The "BL" box will require a firmware file that starts with "BL", the "AP" box will require a firmware file that starts with "AP", the "CP" box will require a firmware file that starts with "CP", and the "CSC" box will require a firmware file that starts with "CSC" (DO NOT USE THE "HOME_CSC" file for the "CSC" box).

10) Go to the "Options" tab and make sure that only the "Auto Reboot" and "F. Reset Time" checkboxes are ticked.

11) Go back to the "Log" tab.

12) Click the "Start" button on bottom right.

13) Sit back and relax for a while. Odin will output what is being flashed in the "Log" and on a box in the top left.

14) The box in the top left will become green and in black letters say "PASS" once the flash was successful.

15) Once the flash finished, disconnect your phone from your computer.

16) Your phone will do an erase at this point, so don't mess with your phone until you reach the setup screen.

17) Continue with the setup on your phone and enjoy!

A HUGE thanks goes to [MENTION=8034635]STF_TimelessGoD[/MENTION] [MENTION=7277512]mweinbach[/MENTION] [MENTION=4214610]MJHawaii[/MENTION] and [MENTION=8288520]juvemex[/MENTION] for their original guides that I based this guide around.

DOWNLOADS:

Standard Odin: https://xdaforums.com/showpost.php?p=75703449&postcount=276

Prince Comsy's Odin: https://www.androidfilehost.com/?fid=24591023225177749

Samsung Drivers: http://developer.samsung.com/galaxy/others/android-usb-driver-for-windows

Canadian HOME_CSC (Bootloader v1): https://androidfilehost.com/?fid=673791459329073007

Canadian HOME_CSC (Bootloader v2): https://androidfilehost.com/?fid=962157660013071342

Factory Binary (Bootloader v1): https://www.androidfilehost.com/?fid=745425885120727548

Factory Binary (Bootloader v2): https://androidfilehost.com/?fid=962021903579500553

Google Platform-Tools (ADB): https://dl.google.com/android/repository/platform-tools-latest-windows.zip

Unlocked Firmware (Bootloader v1): https://androidfilehost.com/?fid=817906626617958528

Unlocked Firmware (Bootloader v2): Use SamFirm.

AT&T S8 Firmware (Bootloader v1): https://www.androidfilehost.com/?fid=817550096634785008

AT&T S8 Firmware (Bootloader v2): Missing (Not even available by using SamFirm due to tight AT&T security) :(