How to Install Stock Firmware on Galaxy S21 or S21 Ultra

Samsung Galaxy S21 and S21 Ultra are the latest smartphones of the Samsung flagship series. Both smartphones come with cutting edge technology and the latest features. The Samsung Galaxy S21 series is running on One UI 3.1 which is a modified version of Android 11. The smartphones come with all it takes to be the best smartphones of 2021. In this guide, we will talk about how to install stock firmware on Galaxy S21 or Galaxy S21 Ultra. The guide is really simple. If you ask me why there can be a need for it. Maybe because your phone software is corrupted. Maybe you rooted your phone now you want to go back to stock settings to receive OTA updates.

In this guide, we will cover two methods that can be used to install stock firmware on Galaxy S21. The first method is via the smart switch, which is a tool for laymen. Everyone can use it and make perform some tasks like making a backup or restoring the firmware. Its basically iTunes for Samsung Devices. The other tool is also an official tool from Samsung, it is used to flash recoveries, custom firmware and stock firmware. It is not easy and straight forward as smartswitch but its more efficient. People who have had experience with flashing and installing the firmware on Samsung smartphones prefer ODIN. As it gives more flexibility and control. It exists long before smart switch was introduced.

Guide to Locate Galaxy S21 via Smart Switch:

Let us start with the smart switch. So people who are going to install stock firmware for the first time can also make use of this method. If you ask me why would someone have to install stock firmware on Galaxy S21. Although, they don’t root their phone or try to flash custom recoveries. Sometimes, the operating system crashes and your Galaxy S21 is stuck at the Samsung logo on startup. A factory reset won’t fix it. The solution to that is also this guide.

For this guide to work, you will have to download and install the windows application of smart switch on your computer. If you are a macOS user. You can download the Mac version of smart switch. The rest of the guide is the same. One advantage the smart switch has over ODIN is that ODIN is not available for computers running on macOS.

Steps to flash a firmware on Galaxy S21:

  1. Once you have downloaded and installed the smart switch on your PC.
  2. Open it and connect your phone to your PC
  3. It will display all the information regarding your phone and its operating system.
  4. Click on “More” on the top right corner of the smart switch and select Emergency Software Recovery.
  5. Now Smart Switch will itself find the latest suitable firmware for your Samsung Galaxy S21 or S20+. You will have an option to select from the firmware.
  6. Select the firmware and follow the on-screen information.
  7. It might take time as the smart switch will download the firmware on your PC. Make sure your phone is connected to your PC all the time during the process. Once the process of installation of new firmware on Samsung S21 is done. Your phone will reboot.

Note: Emergency Software Recovery might ask for a recovery code. If you can not find the recovery code. You can also install stock firmware on your Samsung Galaxy S21 via Device initialization instead of the Emergency Software Recovery option. All you would need is to have your Galaxy S21 model number. You can find the model number of your phone on the back of your phone or on the box of your phone. You will also need your device’s serial number which can be also found on the box of your phone.

The process is pretty simple, I hope you had no issues trying to install stock firmware on Galaxy S21 via Smart Switch.

Install Stock Firmware on Galaxy S21/S21+ or Galaxy S21 Ultra via ODIN:

Installing firmware from ODIN can be really helpful if your phone is dead and isn’t even recognised or detected by your computer. ODIN can be used to perform a number of tasks on your phone that are impossible without it. For example, partitioning the storage, flashing a custom recovery, fixing a bootloop. All can be done with ODIN. ODIN is a very powerful tool and comes in handy in a number of situations. Once you are comfortable using it to tweak your Samsung phone it gets easy performing other tasks like installing a stock firmware.


First of all, you will have to install some prerequisites on your Windows PC.

First of all, download and install Samsung drivers for Windows on your laptop or PC. If you have already installed a smart switch. You don’t need to install the drivers. As your PC will already have them. These drivers are required for your computer to recognise your phone.

Moreover, download the appropriate firmware for your Note 10. If your phone is a carrier-free device. You can download the firmware that belongs to any country. If your phone is carrier-locked then make sure to download the firmware of that respective carrier according to the country you bought the phone in. If you install the exact same firmware that is already installed on your Note 10. All your data will be preserved. Otherwise, you will lose all the data present in the internal storage of your phone. If you install carrier-free firmware on a carrier-locked phone. Your Note 10 will be stuck on the Samsung logo at the startup.

Following is the step to step guide on how to install stock firmware on Galaxy S21 using ODIN:

  1. First of all, turn off your Galaxy S21/S21+ or S21 Ultra.
  2. Now go to Download Mode.
    • In order to access download mode on your phone. Once the phone is off press and hold the Volume down and Volume up button simultaneously. While you are holding the buttons, insert the data cable in the port of the phone.
    • Once you see the warning on the screen. Release the buttons.
  3. Press the Volume up button to proceed to Download Mode.
  4. On your PC, open ODIN and connect your phone using a USB data cable. You will see “Added” in the logs of ODIN.
  5. You will see your phone has a connection with your PC. The ID:COM on ODIN will change to blue. (If the colour didn’t change, then the PC has not recognized your S21. Above all, make sure you have installed the right drivers and the drivers were installed successfully. Sometimes the fault lies in the USB cable)
  6. In ODIN, you will see several tabs and you will have to select files respective to each tab. Click on CP and locate and select the CP file from the extracted firmware. In the same vein, click on AP and select the file with AP in the name. Similarly, add BL file in the BL tab.
  7. If you want to factory reset while you install stock firmware on Galaxy S21. Select CSC file in CSC file. Otherwise, load the HOME_CSC instead.
  8. Make sure F.Reset.Time and Auto-Reboot option are checked in the ODIN. Meanwhile, if there is any other option checked. Uncheck it.
  9. Finally, when all the above steps are a go, press the “Start” button. The whole process will take around 5-9 Minutes. Once done, your phone will reboot.

Note: Do NOT disconnect your S21 from your Windows PC while the flashing is in process. Even if it is stuck at some point. Until you get in logs that the process is finished or your phone reboots itself after successful firmware flashing. If you disconnect your phone in the middle of flashing, you might end up bricking your phone.

Samsung Galaxy S21, S21+ and S21 Ultra Specs and Features:

The Samsung Galaxy S21 Ultra comes with a 6.8-inch screen, the S21+ has a 6.7-inch screen, whereas the S21 has a 6.2-inch display screen. The battery size of Ultra is 5000 mAh. That is quite a lot for a smartphone. It should give days on it. The S21+ has 4800 while the standard S21 has a 4000 mAh battery size. While the storage of each phone is 256 GB the Ultra one comes with an S-pen.

Galaxy S21 Ultra has a 108 MP wide-angle lens, along with a 10 MP Telephoto with 3x zoom, a 10 MP Telephoto lens with 10x zoom. It gives you about 100x zoom in total. The front camera is 40 Megapixels. While the other models come with a 12 MP wide-angle lens another 12 MP ultra-wide lens. A 65 MP telephoto which gives up to 30x zoom. The front camera is 10 Megapixels. Samsung has deployed some heavy machinery in the form of its S21 series, you can get an idea about it from the specs above. All these specs and features come with a hefty price tag too.


I hope this guide helped you to fix your phone by installing stock firmware on Galaxy S21. If you have any questions or queries, drop them in the comments below. The method with ODIN can be a bit complicated for first-timers. So if you have any confusion at any step. Feel free to ask for help. If the guide helped you. Do give us your feedback. If we can improve something above any of the methods above. Share with us.



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