If you are looking for LG Stock Firmware ROM (Flash File) for your LG X400 MK121S, then you have landed at the right place.
On this page, you will find the Official LG X400 MK121S Stock Firmware ROM. The Stock ROM comes in a zip package that contains the Firmware File, Flash Tool, USB Driver, and a How-to Flash Manual.
LG Stock ROM helps you upgrade or Downgrade the Operating System (OS) of your LG Device. It also allows you to fix any Software related issues, Bootloop issues, and IMEI-related issues.
[*] Flash Tool: If you are looking for the official LG Flash Tool, then head over to the LG Flash Tool page.
[*] USB Driver: If you are looking for the official LG USB Driver, then head over to the LG USB Driver page.
[*] Backup: If you are going to flash or install the above Firmware on your LG X400 MK121S, then we recommend taking a backup of your data, as flashing or installing the Stock ROM (Firmware) will wipe the data from the device.
[*] Original firmware: The above firmware is officially released by LG Electronics and is in the original state. We have scanned the Stock ROM package with Kaspersky Internet Security before sharing it online.