Ok so something happened and you want to flash a single stock partition such as boot, recovery or even system without flashing the complete firmware package. This is a quick how to using the Unified Android Toolkit.
PART 1 – DOWNLOADING THE STOCK FIRMWARE IMAGE
1. Go to samsung-updates.com then click on the triangle next to ‘Select Device’ (top left side) and scroll down to your device such as SM-G900F (for the Galaxy S5).
2. A list of available stock firmware images will be displayed. Find the build that you need and click on the “Download” button on the right side. IMPORTANT: Since you only want to flash a single partition make sure that the build you download is the same as the build you have on your device now so that it is compatible with the rest of your partitions. If the same build isn’t available or you can’t access that information and don’t know you want it to AT LEAST be the same version (i.e. 4.4.2).
3. The next screen will give you the option of where to download the image from. In my opinion Rapidgator is a bit faster (for the free download) but will still take a while so you might want to go away and come back when its done.
4. After it’s finished downloading you will have a large zip file. Extract the contents using winzip or 7-zip and you should now have another large .tar.md5 file. This is the file you would load in to Odin (as a “PDA” / “AP”) if you want to flash the complete package but since you just want a single image you need to rename the file to .tar (delete the .md5 from the end) and then extract just the image you need such as the system.img file. If you cannot see the file extensions in your windows explorer you need to open your Control Panel, Appearance and Personalisation, Folder Options then click on the View tab and untick ‘Hide extensions for known file types’. Click apply and OK and you should now see the file extensions.
PART 2 – MAKING THE FLASHABLE TAR FILE
1. So now you should have the image file you want to flash but you need to get it in to a .tar format that can be flashed by Odin. Copy the .img file to the INPUT folder in the Toolkit (v1.2.7 or later) and start the Toolkit. Type option ’99’ to load up the Basic Toolkit. In the Main Menu of the Basic Toolkit select option ‘8’ (Create an Odin flashable tar). In the next menu choose option 2 to make a single tar file from multiple images (it doesn’t matter that you only have 1 image).
2. Make sure that ONLY the image you need to flash is displayed in the list (.img or .img.ext4) and type yes to start. If the file is a system image then it will take a while to convert but eventually it should say completed and you will have a .tar file in the OUTPUT folder. This is your flashable file.
PART 3 – FLASHING THE TAR FILE
1. Once you are back in the Main Menu of the Basic Toolkit select the ‘Device Reboot Options’ section and ‘Reboot to Download Mode and Start Odin’. If you can not boot your device in to Android with adb debug enabled (needed for this option) then just unplug your usb cable, hold Volume Down, Home and Power buttons until you get a warning screen and press Volume Down to get in to Download Mode. Then you can run Odin3_v3.09.exe from Toolkit folder. Now connect your usb cable and the box under ID:COM should be blue.
2. Make sure ‘Auto Reboot’ and ‘F. Reset Time’ is ticked.
3. Click on ‘PDA’ / ‘AP’ and browse to the Toolkit, OUTPUT folder. Click on the tar file (it will start with CREATED-TAR) and then click on Open. When you are ready hit the “Start” button and the flash process should start. This may take a while depending on the image you are flashing. A progress bar will be displayed on the device and on Odin to let you know how it’s going.
4. After the flash finishes your device will reboot and if everything went fine the new image will be flashed and your device should boot without any problems.
That’s it, I hope this helps out whoever needs it.