LG K31 Root, Bootloader Unlock, TWRP lmk300qm Rebel l355dl

In the earlier days of Android, rooting was quite easy. It was possible to root the phone via one-click rooting apps without using a computer.  I rooted my LG Tribute 5 in a single click even without unlocking the bootloader.

However, nowadays we need to follow the long path. To root my LG K20 plus I unlocked the bootloader, installed a TWRP custom recovery, and then flashed a Magisk/SuperSU root file via TWRP.

Let’s follow the same procedure for LG K31 as follows –

How to root LG K31 Rebel l355dl Spectrum lmk300qm

First of all, we need to enable USB Debugging and OEM Unlock in the Developer Options.

So, let’s open the Settings app. Pull down the notification panel and tap the “Settings icon”.

Scroll down and open the “System” page.

Now, select “Developer Options” on the System page.


To unlock the Bootloader we need to enable OEM unlock.

Look for “Enable OEM unlock” and tap on it.

Hit “Enable” to allow OEM unlocking. Once it’s turned on the Google’s FRP (Factory Reset Protection) is disabled.


Now, we need to scroll down and enable “USB Debugging” in the same manner.

In the next step, we need to connect our K31 to the computer for USB Debugging.


Let’s grab a micro USB cable and connect our K31 to the computer as shown above.

A notification on the phone reads USB Debugging connected.

Now, let’s wait for the ADB Interface driver to install.

On my PC the LGE Mobile ADB Interface driver is installed. We can check the installation status in the device manager.

For USB Debugging we need a Minimal ADB and Fastboot Tool.

I’ve installed this tool on my PC.

The Minimal ADB & Fastboot tool launches the command prompt window.

To check the ADB connection we can write the command adb devices

The output of this command line is LMK300 unauthorized

Here LMK300 is the model number of LG K31.  The PC is unauthorized for USB Debugging.

To authorize it, you need to check your phone screen.

The must be an “Allow USB debugging” prompt on your K31 screen.

Hit “Allow” to authorize the connected computer for USB Debugging.

Once again, I wrote the same command. The output has changed to LMK300 device

Now, let’s try to boot our K31 into fastboot mode for Bootloader unlocking –

LG K31 Bootloader Unlock

To unlock the bootloader we need to put our K31 into Fastboot Mode.

The command line for the same is adb reboot bootloader

I wrote this command and hit enter on my PC keyboard.


This simply restarted my LG K31. I didn’t get access to the fastboot mode.

Now, let’s try another command.

One more command for the Fastboot mode is adb reboot fastboot

Type this command and click enter on your PC keyboard.

Our K31 is now in the Fastboot mode.

There are 4 options on this page are –

Reboot System now, Enter Recovery, Reboot Bootloader & Power off.

We are interested in Bootloader unlocking, so let’s select the 3rd option i.e. “Reboot to bootloader”.

In the fastboot mode, touch doesn’t work. We need to move down to the 3rd option using the volume down button.

Now, hit the power button to select the option “Reboot to bootloader” as shown above.

Unfortunately, the phone rebooted once again to the home screen.

The access to the bootloader unlocking is blocked on LG K31.


LG K20 Plus Bootloader Unlock

The Fastboot Mode for bootloader unlock page on my K20 Plus looks like this.

We just need to write the command fastboot oem unlock for bootloader unlocking.

Unfortunately, we don’t get access to this page on our K31.

We cannot root our LG K31 without unlocking the bootloader.

LG K31 TWRP Custom Recovery

A custom recovery such as TWRP can be flashed only after unlocking the bootloader.

As we failed to unlock the K31 bootloader, it’s not possible to install TWRP.

LG K31 Lineage OS Custom ROM


A custom ROM such as lineage OS is in the form of a flashable zip file. Like the Magisk or SuperSU root, we need to flash this zip file via TWRP.

Without custom recovery, it’s not possible to flash a custom ROM on LG K31.

Now, that you’ve gained access to USB debugging you may like to move apps to SD card on LG K31 –

How to move apps to SD card on LG K31


How happy are you with your LG K31? Please share your experience in the comment section below.



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