Firmware Samsung Galaxy S21 Ultra

OS: Android v11

CPU: Octa core (2.9 GHz, Single core, Cortex X1 2.8 GHz, Tri core, Cortex A78 2.2 GHz, Quad core, Cortex A55)

RAM: 12 GB

Display: 6.8 inches (17.27 cm)

Battery: 5000 mAh

Before flashing, you need
Create a full backup of the firmware.
The battery must be 100% charged.

1. Flashing your phone using CWM Recovery
2. Flashing the phone using TWRP Recovery
3. Flashing the phone using Fastboot

1. Phone flashing using CWM Recovery
The rich functionality of CWM Recovery www.clockworkmod.com allows you to perform many manipulations with the device, including rolling the firmware. By default, stock Recovery is installed in the devices, which means that first you need to install the ClockWorkMod Recovery utility itself.
The general firmware process described below is for ZIP files. Instructions: - Download the firmware you are interested in and place it on the phone's SD card.
- First, turn off the phone with the Power button.
- Press a certain combination of buttons on the phone body, it may vary depending on the phone manufacturer. If you don't know the combination you want, try pressing the following keys.
- Press the Power + Volume up (or Volume Down) (+Home) buttons together for a few seconds.
- The phone will boot into Recovery mode.
- Use the volume buttons to navigate through menus and the Power button to make selections.
- Select 'Wipe data / factory reset' from the menu.
- Select 'Yes - delete all user data' and press the Power button.
- Use the volume buttons to select 'Wipe cashe partition' .
- Select 'Yes - Wipe cache' and press the Power button.
- Select 'advanced' and press the Power button.
- Select 'Wipe Dalvik Cache' and press the Power button.
- Use the volume buttons to select 'Yes - Wipe Dalvik Cache'.
Go back, press 'Go Back'.
- Select 'mounts and storage' and press the Power button.
- Select 'format / system' from the menu.
- Use the volume buttons to select 'Yes - Format' .
Go back, press 'Go Back'.
- Select 'install zip from sdcard' .
- From the menu, choose 'choose zip from sdcard' .
- Use the volume buttons to select 'Yes - Install your firmware name' .
- Then select 'Reboot system now' .

2. Flashing the phone using TWRP Recovery
For those who prefer working with the utility in the form of TWRP Recovery, the following instructions for the step-by-step installation of the update in the form of a ZIP archive are offered:
- Upload the file with the firmware image to the device's memory.
- Go to TWRP Recovery. In the same way as in CWM.
- Perform a factory reset by tapping the 'Wipe' option in the main menu. When finished cleaning the phone, return to the original menu by pressing the 'Back' key.
- From the main menu select 'Install' and find and select the firmware file. Click on it by dragging the slider to the side.
- The phone flashing process will end in 2-3 minutes.
- Upon completion, the utility will automatically display a message about successful flashing. By clicking on the item 'Reboot System', reboot the device.

3. Flashing the phone using Fastboot
A universal tool for flashing Android smartphones using a PC is the Fastboot utility. It is part of the SDK Platform Tools, which means it is suitable for a large number of devices.
Before starting the firmware, you need to get access to the system kernel. Very often, many manufacturers block this system parameter, not wanting users to change the system files of their firmware images with their own hands. To do this, you need to unblock Bootloader. To do this, you need to study the detailed instructions for configuring and managing the command line. Before starting the firmware using a computer, do not forget to enable USB debugging of the device in the engineering settings of the device.
- First, copy the .zip archive with the image, and place it in the folder with 'ADB'.
- Now you need to put your device into fastboot mode and write a prompt in the command line: fastbooflash zip filename.zip.
- Wait until the end of the installation and reboot the device.