ICS ROM for LG L3 E400

Pre Requisites to Update ICS official CM9 ROM on LG L3 E400:

We recommend you to take a backup of your all data. Because after installing the ROM your previous data will be lost.
SMS – How to Backup Messages
Contacts – Sync with Gmail App
Videos, Images, Songs and Other Files – Copy to internal / External SD card or System
APN Settings – Take Manual Note from “Settings > Wireless & Networks > Mobile Networks > Access Point Names
And have minimum 60% charge in your mobile battery. This will help your phone to don’t get switched off.

First your phone must be rooted. Check this – How to Root LG Optimus L3 E400
And You need to install ClockWorkMod Recovery – How to install ClockWorkMod Custom Recovery on Lg Optimus L3
Download the Official ICS CM9 ROM – Here
Connect your phone with PC using USB Cable.
Transfer the downloaded file to your SD card.
Then you need to restart your phone in Recovery mode. Switch off the phone and restart in Recovery mode by pressing, Power Button + Volume Down + Menu button together.
Then you will move on to ClockworkMod Recovery page. You can navigate using Volume buttons and select an option by pressing Menu or Home button.
Now select Wipe option and make Wipe data. And also do Wipe Dalvik Cache.
Then select “Install Zip from SD Card” and select “Choose zip from SD card”.
And browse and select the downloaded file in SD Card.
In a few seconds the ICS official CM9 ROM will be installed on your LG Optimus L3 E400.
Then select “Go Back” and then select “Reboot System Now”.