This is a custom ROM, based on AOSP release of the Android 5.1.1 Lollipop.
We haven’t really found any major issues or apps that do not work with this Android 5.1.1 CM12.1 custom firmware.
•This tutorial is only for installing Android 5.1.1 CM12.1 Nightly ROM on LG Optimus G. Please do not try on any other Optimus G variants.
•Your phone should have a custom recovery installed and should be rooted (optional) from before.
•This tutorial will wipe out all your data.
•Make sure you backup all your data in your phone before proceeding.
•Perform a Dalvik Cache wipe before proceeding from the Recovery Mode.
Androidromfix provide various Firmware Updates and Rooting process along with Custom ROM,Modes,file are all belong to their owners/developers. The autor of this site or the developers are not responsible, if you damage or brick your device.Do it on your own risk and follow the instruction properly.
÷ How to Install Android 5.1.1 CM12.1 Nightly Lollipop on LG Optimus G
Step 1- Download Android 5.1.1 CM12.1 Nightly ROM and Gapps for Optimus G to your computer.
Step 2 - Connect and mount your Optimus G USB memory to your computer using the USB cable.
Step 3 - Now copy/paste the downloaded Android 5.1.1 ROM zip and Google Apps zip files to your phone memory / SD card. Make sure the file is in the phone memory / SD card root (not in any folder).
Step 4 - Then turn OFF your phone and disconnect from the USB cable.
Step 5 - Now to get in the Recovery Mode. Switch ON the phone while pressing and holding Volume Up + Power buttons together.
Step 6 - Once you are in ClockworkMod Recovery, select perform a full data wipe by selecting “wipe data/factory reset” . Use the Power button to select everything while in the Recovery Mode.
Step 7 - Then, perform a cache wipe by selecting “wipe cache partition” as you can see in the image below.
Step 8 - Now this is optional, but it is recommended to perform a wipe of your dalvik cache as well. You will not get into boot loops or any other errors. From CWM recovery, go to ‘advanced’ and then select “wipe dalvik cache”.
Step 9 - Then go back to the main recovery screen and select “install zip from SD card”.
Step 10 - Now select “choose zip from sdcard”. Using your volume keys, navigate to the Android 5.1.1 ROM zip file that you copied to your SD card and select it using the Power button. Confirm the installation on the next screen and the installation procedure should start now.
Google Apps: Repeat the above step for the Google Apps zip file as well and install it on your phone.
Step 11 - After the installation completes, go to “+++++Go Back+++++” and reboot the phone by selecting “reboot system now” from the recovery menu .
Your Optimus G will boot now and it might take about 5 minutes to boot on your first time. So, please wait.
That’s it! Your LG Optimus G should now have Android 5.1.1 CM12.1 Nightly Lollipop custom ROM installed on your phone! Go to Settings > About phone to verify.