All Android phones come with built-in recovery mode that is separate from the original operating system.
The recovery mode is used to access different features of the phone without accessing the phone’s OS.
The main function of the recovery mode is to fix the phone while staying away from the faulty OS of the phone.
1. First thing you got to do to start the process is turning off your phone
2. Then press volume down button and power button and hold them untill next step.
3. When you will see LG logo on your screen you can release those buttons.
4. Now there should be a recovery mode menu on your screen.
5. If you see this screen it means you did everything correctly, congratulations.
Recovery, in Android, refers to the bootable partition, in which the recovery console is installed.
It contains tools to help repair your installations as well as install official OS updates by using a combination of key presses or instructions from a command line sometimes.
Android is open, meaning the recovery source code is available, so that building a customized ROM is relatively easy.