Some important instructions must be taken into considerations. First check the battery of your LG G2. The device needs to have at least 80 percent battery level to prevent power interruption issues during the upgrade process. Also you need to create a backup of all the important data, files and settings stored on your phone. It is important as flashing a custom ROM can wipeout all the phone’s memory. The complete info of this Android 5.0 Lollipop based Cyanogenmod 12 custom ROM is given below. Also the list of working features is given below. You can have a look at it.
LG G2 Android 5.0 Lollipop CM 12 ROM screenshot 1
Cyanogenmod 12 ROM info:
  • ROM OS Version: 5.0.x Lollipop
  • ROM Kernel: Linux 3.4.x
  • Based on: Cyanogenmod
  • Status: Testing
  • ROM firmware required: Jellybean bootloader
  • Build date: 18 November
LG G2 Android 5.0 Lollipop CM 12 ROM screenshot 2
Working List:
  • Camera
  • WiFi
  • All native apps
  • All accelerometers/sensors
  • Airplane Mode
  • Most audio
  • Display
  • Most Project Volta related enhancements
  • Notification lights
  • RIL
  • NFC
  • Wi-Fi tether
  • Google Apps
Note that this CM 12 build is not so stable. You might face some bugs or issues while using this. But with further stable updates all these bugs can be cleared out. Interested users can head on to our actual Android 5.0 Lollipop based Cyanogenmod 12 custom ROM on your LG G2 smartphone.
LG G2 Android 5 L CM 12 screenshot 3
Disclaimer:
The process of updating LG G2 to Android 5.0 Lollipop based Cyanogenmod 12 custom ROM is considered to be of much risk and even a slight change can highly damage your phone. So you need to attempt it correctly and at your own risk. Neither we nor the developers are responsible if your LG G2 gets crashed. Although the chances of getting you device damaged or bricked are least but still I strongly recommend you to follow all the instructions perfectly without a single mistake.
Compatibility:
The CM 12 update given below is compatible only and only with LG G2 model number D800, D801, D802, LS980, VS980. So don’t flash it if you’re having another device  or variant as this may damage the phone. You can verify the given number with your device’s model number from Menu->Settings --> About Phone.
LG G2 Android 5.0 Lollipop CM 12 ROM screenshot 4
Pre-Requisites:
  • Your phone may get switched off during the flashing process due to low battery life. Hence it is strongly recommended to charge the battery of your mobile at least up to 60%.
  • Always remember to backup all your Phone data and settings including contacts, call logs, messages, memos, whatsapp messages etc. to external memory card or on your PC since it gets wiped in the last step of this procedure.
  • Backup EFS present in your phones system directory. This folder contains all your phones specific information such as the IMEI, wireless devices MAC addresses, product code, and much more. So a backup of this folder is essential. There is always a risk that this EFS folder might get corrupted. If so happened, your device will be completely useless & will no longer be recognized by your carrier.
  • Make sure you have installed mobile specific drivers on your PC. This is recommended so as to recognize your LG G2 when connected via USB cable. You can manually install them from the link given below:
  1. Download LG G2 USB drivers.
  • Your LG G2 must be rooted.
  • You must have installed a custom recovery like Clockworkmod (CWM) or TWRP on your LG G2 before proceeding further.

Procedure to install Android 5.0 Lollipop on LG G2 [CM 12]:

Downloads:
  1. Download CM12 for LG G2 D800.
  1. Download CM12 for LG G2 D801.
  1. Download CM12 for LG G2 D802.
  1. Download CM12 for LG G2 LS980.
  1. Download CM12 for LG G2 VS980.
  1. Download Google Apps (Android 5.0 Lollipop).
Procedure:
Step 1: Download the zip package files in a specific folder on your PC. Do not extract them.
Step 2: Then connect your LG G2 to your PC, enable USB debugging mode and copy the downloaded files on your phones SD card.
Step 3: After copying, safely disconnect your LG G2 from PC & switch it off completely. Now boot your phone into custom recovery mode. For that, press and hold Volume up + Home button (middle button) + Power button together till you land into custom recovery mode.
Note: After you land into recovery mode, make a complete Nandroid backup of the ROM which you are currently using. The nandroid backup is the backup of your phones entire operating system & is always helpful during the failure while flashing process or during any problem with the ROM, then you can easily restore your saved previous ROM.
Step 4: For taking the backup of your current ROM, navigate to the ‘backup & restore’ option on the recovery mode itself and on the next screen select ‘backup’ option. This will make a complete nandroid backup of your current ROM. Note that this will be saved on your phones SD card. Refer screenshots.
Nandroid backup screenshot 1Nandroid backup screenshot 2
Step 5: Then wipe the data and cache partitions from your phones internal memory. So navigate to the ‘wipe data/factory reset’ option present on the recovery mode. Select it and on the next screen press Yes option to start the wiping process. Similarly navigate to the ‘wipe cache partition’option on the recovery mode and select it to wipe the caches. This step will clear all the data & caches from your phone. So you must take a complete backup before doing this step (Refer Pre-requisites section).
CWM wipe data cache screenshot
Step 6: Return to the main menu and select theAdvanced option. On the next screen select Reboot Recovery  option.
reboot recovery screenshot
Wait until you boot again into recovery.
Let’s move to the actual Android 5.0 Lollipop based CM 12 ROM flashing process.
Step 7: On the main screen of the recovery you’ll find the ‘install zip from SD card’ option. Select it and then on the next screen select ‘choose zip from SD card’ option. This will show all the data present on your external SD card along with the Android 5.0 Lollipop based Cyanogenmod 12 ROM which you’ve just copied earlier. So select it and on the next screen select ‘Yes’ option to start the actual Android 5.0 Lollipop ROM flashing process. You need to wait for some time to complete it successfully.
CWM recovery Screenshot
Step 8: After the process completes, press back button to return to the main menu. Again select ‘wipe data/factory reset’ option and ‘wipe cache partition’ option as you did before to clear all your phones data & cache. This step is essential to solve the boot loop issue.
Step 9: Similarly flash the Google Apps (GApps) as you’ve flashed this Cyanogenmod 12 custom ROM. Just remember not to wipe data/cache after flashing them.
Step 10: Restart your LG G2 by selecting ‘reboot system now’ option from the recovery mode. This first boot will take more time to start than usual.
reboot system screenshot
Note: If you want to restore back your previous Rom, then you can do that by going back to the recovery mode by pressing & holding Home Button (middle button) +  Power Button simultaneously and select ‘Backup and Restore’ option and then on next page select ‘Restore’ option. Select the ROM you want to restore.
Success
Well done! The latest Android 5.0 Lollipop based Cyanogenmod 12 Custom ROM has been successfully flashed on your LG G2 D800, D801, D802, LS980, VS980 smartphone. Go to Menu->Settings->About Phone and confirm it. Enjoy the all new features and customization on your device after flashing this CM 12 ROM. Also share your experience after using it. If you face any kind of difficulty then feel free to text us through the comments section below. I’ll try to provide a solution for your each problem. Enjoy! :-)