Errors constantly appear in the Android operating system.
Some installed applications stop opening.
Many programs from the Play Market do not work.
The phone restarts for no reason.
The phone began to slow down a lot.
You are not satisfied with the functionality of the stock (official) firmware.
Where can I find the firmware?
On the official website of the phone manufacturer.
On sites where third-party developers post custom operating systems.
What should be done before installing the firmware?
Back up your phone's user data.
Insert your SD card into your phone. An SD card is needed to write firmware to it.
Determine your smartphone model.
Fully charge your phone. If the battery runs out during boot, the device will no longer turn on.
Download archive with Firmware. Place it on the SD card.
Installing TWRP Recovery
Download the Official TWRP App from the Play Market. And install it.
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.
On the next screen, select 'TWRP FLASH' and give the application root rights.
On the main screen of the application, click on the 'Select Device' drop-down list, and select your phone model.
After selecting a device, the program redirects the user to a web page to download the corresponding image file of the modified recovery environment. Download the suggested *.img file.
When the download is finished, you need to return to the main screen of the Official TWRP App and click on the 'Select a file to flash' button. Select the file downloaded in the previous step.
Click the 'FLASH TO RECOVERY' button and confirm your choice, click 'OK' in the question window.
When the message 'Flash Completed Succsessfuly!' appears. Click 'OK'. The TWRP installation procedure can be considered complete.
Transfer the necessary files to the SD memory card. Using a PC or laptop card reader, it will be much faster.
Insert a memory card into the phone.
To reboot into recovery, you need to use a special item in the Official TWRP App menu, accessible by pressing the button with three stripes in the upper left corner of the main screen of the application. Open the menu and select the 'Reboot' item, and then click on the 'REBOOT RECOVERY' button.
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.
Now you can start flashing. Press the 'Install' button.
The file selection screen appears. 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.
Select the firmware file 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.
After completing the installation procedure, a 'Successful' message appears on the screen.