The phone shuts down and restarts for no apparent reason.
The phone began to slow down a lot.
You want to update the firmware, as it does not suit you in terms of functionality.
Where can I find the firmware?
On the official website of the manufacturer.
On specialized services where users post custom or official OS.
What should be done before installing the firmware?
Back up your contacts and user data and transfer it to another medium.
Insert your SD card into your phone. An SD card is needed to write firmware to it.
Determine your smartphone model.
Fully charge your device's battery.
Find and download the archive with Firmware.
Installing TWRP Recovery
Download the Official TWRP App to your phone from the Play Market. And install this app.
When you start the application for the first time, you need to give consent to future manipulations, as well as to give consent to granting the application Superuser rights and click the 'OK' button.
In the next screen, select the item 'TWRP FLASH' and provide the application with root-rights.
On the main screen of the application, click 'Select Device', and find your phone model.
After selecting the phone, the application will redirect the user to a web page to download the modified recovery environment image file. Download the proposed *.img file.
When the file is loaded, you need to return to the main screen of the Official TWRP App and press the 'Select a file to flash' button. Select the file downloaded in the previous step.
After adding the image file to the program, click the 'FLASH TO RECOVERY' button and confirm your choice, click 'OK'.
When the message 'Flash Completed Succsessfuly!' appears. Click 'OK'. The TWRP installation procedure can be considered complete.
Copy the required files to the memory card. Using a PC or laptop card reader.
Insert a memory card into the phone.
To reboot into recovery, you need to enter the menu accessible by pressing the button with three stripes in the upper left corner of the main screen of the application. Select the 'Reboot' item, and then click on the 'REBOOT RECOVERY' button. The phone will reboot into the recovery environment automatically..
Firmware via TWRP
Before flashing, you need to delete all user data from the phone, this will avoid errors in the software, as well as other problems. Press 'WIPE' on the home screen.
You can start flashing. Click the 'Install' button.
The file selection screen is displayed. At the very top is the 'Storage' button, select the location where the firmware file is located.
Select the storage to which the files were copied.
Find the file we need and click on it. A screen opens with a warning about possible negative consequences, as well as the item 'Zip signature verification'. This item should be checked by placing a cross in the check-box, which will avoid using damaged files when writing to the phone's memory sections.
The procedure for flashing the phone will begin, this is accompanied by the appearance of inscriptions in the log field and the movement of the progress bar.
When the procedure for installing the firmware is completed, the message 'Successful' appears on the screen.