Some applications do not open, reinstalling which does not lead to a positive result.
Many programs from the Play Market do not start.
The phone restarts for no reason.
The phone began to slow down a lot.
You are not satisfied with the possibilities of the stock firmware.
Where can I find the firmware?
On the website of your phone manufacturer.
On specialized services where users post custom or official OS.
What should be done before installing the firmware?
Back up your phone's user data.
Insert an SD card into your phone to write the firmware to it.
Determine your smartphone model.
Fully charge your device.
Find and download the archive with Firmware.
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, you need to select the 'TWRP FLASH' item and give the application root-rights.
On the main screen of the application, click 'Select Device', and select your phone model.
After selecting a phone, the application will direct 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.
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.
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 'Reboot' and then click on the 'REBOOT RECOVERY' button.
Firmware via TWRP
Before flashing, you need to clear the 'Cache' and 'Data' sections, press 'WIPE' on the main screen. You will delete all user data from the phone, this will avoid software errors and other problems.
You can start flashing. Click the 'Install' button.
The file selection screen is displayed. At the very top is the 'Storage' button, which allows you to switch between types of memory.
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 writing files to the phone's memory will begin, this is accompanied by the appearance of inscriptions in the log field and the movement of the progress bar.
After the firmware installation procedure is completed, the 'Successful' message appears on the screen.