Step-1: Transfer both “Firmware” and “Gapps” .zip files to your device internal storage
(Don’t extract these files/ don’t place these files in the subfolder of device internal storage)
Step-2: Disconnect your device from your PC and switch off.
Step-3: Now boot your device into Recovery Mode
*Press hold volume down+ Power button > Release after LG logo appears > Press again immediately until reset menu displayed, > Press power button three times.
*Use Volume keys for navigation between the options here
Step-4: Create an image/backup of your existing ROM by Nandroid backup. Which you can restore if there is any issue in this new ROM
* In recovery mode select backup and restore > select backup > back after backup process finished
Step-5: Now perform data Wiping task, on the recovery mode screen
i) Select Wipe data/Factory reset> select YES> Go back to recovery mode
ii) Select Wipe cache partition> confirm by YES >Go back to recovery mode
iii) Under Advance option select Wipe Dalvik Cache > Go back to recovery mode
Step-6: Select Install Zip from SD Card > Choose Install zip from sdcard > Locate the Firmware .zip file> Press Power button to select> Click YES-Install_______.zip to confirm ROM installation.
Step-7: After ROM installation process complete, Repeat Step 6 once more but this time, choose gapps-lg-________.zip to install the Google apps package.
Step-8: NOW repeat Step-4 once more to create image the new installed ROM and go back to main recovery menu
Step-9: Now select Reboot System Now to reboot your LG device into new installed ROM.
To Return on Previous ROM: Boot your device into recovery mode > select “backup and restore” then select Previous ROM backup from the list to restore your previous ROM.
These were the steps on CWM Recovery that you had to follow in order to install firmware on LG devices.
Cheers! Your new firmware is now successfully installed and running on your device
In case of any query do comment us.