Android recovery is a bootable partition, which lets you apply official system updates from SD Card, factory reset your phone or wipe its cache partition.
How to enter LG Optimus L3 E400 recovery mode ?
Power off your device.
Boot in recovery mode by pressing and holding Volume Down and Power Button at the same time.
Release all buttons when the LG Optimus L3 E400 screen flickers and in a few seconds the Recovery screen will appear.
If the above-mentioned
method doesn't work for you, you can try the following
Power off your device.
Wait a few seconds
Boot in recovery mode by pressing the Volume Down and Power Button at the same time for 2-3 seconds until the LG logo appears on the screen.
Release the buttons and press them again until the Recovery Screen appears