You are not satisfied with the possibilities of the stock firmware.
Where can I find the firmware?
On the official website of the manufacturer.
On sites where developers post custom or official OS.
What should be done before installing the firmware?
Create a backup copy of user data and transfer it to your computer.
Insert your SD card into your phone. It must have enough memory to fit the firmware.
Determine your smartphone model.
Fully charge your device's battery.
Download archive with Firmware. Place it on the SD card.
Installing TWRP Recovery
Install the Official TWRP App via the Play Market. And run this application.
When you start the application for the first time, you must agree to install a new firmware and all the risks associated with this, as well as agree to grant 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 select 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.
After downloading the image file, 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.
Press the 'FLASH TO RECOVERY' button and confirm your choice.
When the message 'Flash Completed Succsessfuly!' appears on the screen. Click the 'OK' button. The TWRP installation procedure is now complete.
Write the firmware to the SD card. Using a PC or laptop card reader.
Insert a SD 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, it is recommended to clear the 'Cache' and 'Data' sections. This will delete all user data from the device, but avoid a wide range of software errors and other problems. You must press 'WIPE' on the main 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 location where the files were copied. Press the 'OK' button.
Select the firmware file and click on it. A screen opens with a warning about possible negative consequences, you need to check the item 'Zip signature verification', which will avoid using corrupted files when writing to the phone's memory sections.
The procedure for writing files to the phone's memory will begin, accompanied by logging and filling in the progress bar.
After the firmware installation procedure is completed, the 'Successful' message appears on the screen.