Firmware Samsung Galaxy A21

OS: Android v10 (Q)

CPU: Octa core, 2.3 GHz

RAM: 3 GB

Display: 6.5 inches (16.51 cm)

Battery: 4000 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.
- Turn off your smartphone.
- Press a certain combination of buttons on the phone, the combination may vary depending on the manufacturer of the phone. If you do not know the required combination, try pressing the following keys.
- Press the buttons: Volume up (or Volume Down) (+Home) + Power together for a short time.
- You will see Recovery mode.
- Use the volume buttons to navigate the menu, and use the Power button to select.
- Select 'Wipe data / factory reset' from the menu and press the Power button.
- Then select 'Yes - delete all user data' from the menu.
- Then select 'Wipe cashe partition' from the menu.
- Then select 'Yes - Wipe cache' from the menu.
- From the Recovery mode menu select 'advanced' .
- Then select 'Wipe Dalvik Cache' from the menu.
- Then select 'Yes - Wipe Dalvik Cache' from the menu.
Go back, press 'Go Back'.
- From the menu select 'mounts and storage' .
- Select 'format / system' from the menu and press the Power button.
- Then select 'Yes - Format' from the menu.
Go back, press 'Go Back'.
- Select 'install zip from sdcard' .
- Choose 'choose zip from sdcard' from the menu.
- After that, select the item 'Yes - Install your firmware name' from the menu.
- Next from the Recovery mode menu 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. This is done according to the model with CWM.
- Perform a factory reset. When finished cleaning the phone, return to the original menu by pressing the 'Back' key.
- In the main menu, select 'Install' and find the previously downloaded firmware image. Click on it by dragging the slider to the side.
- The process of flashing the phone will take 2-3 minutes.
- Upon completion, the utility will automatically display a message about successful flashing. Click on the 'Reboot System' item, and 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.
- Copy the .zip archive with the firmware image to the folder with 'ADB'
- Put your device into fastboot mode and write the prompt in the command line: fastbooflash zip filename.zip.
- Wait until the end of the installation and reboot the device.

Thomas Nilan
Smartphone Expert

Thomas Nilan is a mobile phone expert with in-depth knowledge of the Android and iOS operating systems, who understands the settings of various hidden features that allow you to expand the capabilities of your smartphone, as well as get information about what is going on inside the phone for future repairs. He is an authority in his field, which has allowed him to become a ghostwriter for several technology publications, and he enjoys writing small mobile applications for testing smartphones.