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

LG K30 & K40 Dark Mode – How to turn ON

There are 2 ways to turn on the Dark Mode on LG K40 & K30. You can enable it by turning on “High Contrast Screen” in the Accessibility Settings or by activating “Maximum Mode” which is a battery saver mode and can be enabled in the Battery settings.

Lets’ check out these modes with the help of the video and screenshots below –

How to Enable Dark Mode on LG K40 & LG K30

Dark Mode on K30 /K40 is like a Dark theme with a black background. Even the keyboard is darkened in this mode.

If most of the time you are using your phone indoors in low light conditions, then this mode may suit you. Moreover, if you enable dark mode in the form of Maximum Battery Saver Mode you would almost double the battery life of your K30 / K40 as compared to regular mode.

1. High Contrast Screen – LG K30 / K40

LG K30 Dark mode

The first Dark Mode is the High Contrast Screen.

Read moreLG K30 & K40 Dark Mode – How to turn ON

How to Unlock LG K40 Free – LM-X420MM / LMX420AS / LMX420TM / LMX420QM6

In this post, we are going to unlock LG k40 for free without paying for any unlock service or unlock code. Mine is a MetroPCS K40 with model number lmx420mm.

There are six LG K40 variants. Out of these, one is factory unlocked so no need to unlock it. It is compatible with all the major GSM and CDMA carriers in the USA.

The rest of the k40 variants are –

LG K40 AT&T lmx420as
K40 MetroPCS lmx420mm
K40 T-Mobile lmx420tm
K40 Spectrum Mobile lm420qm6
K40 US Cellular lmx420qm

The unlock method differs from carrier to carrier. Let’s start with the MetroPCS / T- mobile LG k40

1. How to unlock LG K40 for free – MetroPCS lmx420mm /T Mobile lmx420tm

LG K40 MetroPCS unlock free

A MetroPCS /T-Mobile k40 can be unlocked using the pre-installed device unlock app.

Look for the “Metro by T-Mobile” folder on the home screen.

Open the folder and select the “Device Unlock” app as shown in the above screenshot.

Read moreHow to Unlock LG K40 Free – LM-X420MM / LMX420AS / LMX420TM / LMX420QM6