LG K40 Drivers LM-X420 – USB, ADB, Windows 10 & Mac

There are many instances when we need to connect our LG K40 to the computer. A successful USB connection is established only after the proper installation of the USB driver.

The LG K40 drivers needed for different kinds of USB connections are MTP driver for file transfer, ADB interface driver for ADB mode or USB debugging and USB serial port driver for download mode or firmware update via LGUP flash tool.

Let’s download the LG K40 Windows 10 / Windows 7  driver and learn how to establish a successful USB connection between our K40 and the computer by installing it –

How to install LG K40 USB Driver – Windows 7 & 10

Download the Latest LG K40 Driver for Windows and Mac from the respective download links –

LG K40 Mobile Driver v 4.4.2 – Download the setup file and save on your computer

Read moreLG K40 Drivers LM-X420 – USB, ADB, Windows 10 & Mac

Root LG K40 LM-X420 / Bootloader Unlock & TWRP

LG K40 can be rooted after unlocking the bootloader and flashing a custom recovery such as TWRP. Using the custom recovery we can install a flashable Magisk or SuperSU zip file to root the device.

I’m trying to root my LG K40 MetroPCS with model number LM-X420MM. There are different variants of K40 based on different carriers. The other K40 variants are T-Mobile lmx420tm, AT&T lmx420as, factory unlocked lmx420qn, US Cellular lmx420qm & Spectrum Mobile lmx420qn.

Let’s start the procedure by unlocking the bootloader.

LG K40 Bootloader Unlocking – LMX420MM

To unlock the LG K40 bootloader we need to do the following steps –

1. Turn on the “Developer Options”

“Developer Options” is hidden by default but can be enabled quite easily. Follow this post to enable it on your K40 – LG K40 Developer Options.

2. Enable USB Debugging

After doing the first step, Go to Developer Options and enable USB Debugging.

lg k30 root

3. Connect K40 to PC via USB Data Cable

Now we are ready to connect our phone to the PC via USB data cable.

lg k30 lge mobile adb interface driver

Wait for the LGE Mobile ADB interface driver to install, after connecting the phone.

4. Use Minimal ADB & Fastboot Tool for Bootloader Unlocking

Read moreRoot LG K40 LM-X420 / Bootloader Unlock & TWRP

LG K40 Developer Options & USB Debugging- How to Turn on LMX420

“Developer Options” is found in “Settings” on LG K40 but its kept hidden by default. The options in this menu are useful for developers. It has got an extensive list of options that can do some harm if misused. That’s why its kept hidden.

However, it’s very easy to enable. Without the Developer Options, we cannot turn on USB Debugging to connect out K40 in ADB / Fastboot Mode. For writing, ADB commands the phone should be connected to the PC with USB Debugging in the enabled state.

In this post, we are going to learn, How to enable Developer Options and USB Debugging with the help of the below video and screenshots –

How to turn on Developer Options & USB Debugging on LG K40

lg k40 developer options

On your LG K40 Home Screen, swipe right and you would see the “Settings” icon. Tap on it to open.

In Settings, select the “General” tab and scroll down to the bottom of the page.

Choose the 2nd last option i.e. “About Phone”.

On the About Phone page, tap “Software Info” as shown above.

Read moreLG K40 Developer Options & USB Debugging- How to Turn on LMX420