This is the operating system that came pre-installed on the phone (Android 2.3.6 Gingerbread). Stock firmware is essential for:
Unlike modern iOS or highly-skinned Android, the L3’s firmware contained deep service menus accessible via dialer codes. For technicians, the code 3845#*400# opened the . Here, you could: Firmware LG E400 Optimus L3
: To install official firmware, you generally need the LG Flash Tool or the older KDZ Updater . This is the operating system that came pre-installed