Soft Reset can fix most of the temporary K51 problems such as app crashes, lagging, black screen, overheating, sound issues, charging problems, etc. If the soft reset fails to resolve the issue, try safe mode.
Only when soft reset & safe mode fails to restore your K51, you should go for a factory or hard reset. A factory data reset erases all the internal storage data including apps, games, texts, call logs, media files, etc. You should always create a backup before doing a reset.
In this post, we are going to learn how to reset LG K51, including soft reset, factory reset via Settings app & hard/master reset via the Recovery Mode when locked out –
How to Soft Reset / Force Restart LG K51?
A soft reset is the most basic form of troubleshooting on LG K51. It can resolve most of the issues.
In Soft reset, we turn off & turn on the phone. Also known as a restart.
Long-Press the power button to get the power options on the screen.
Select “Power off and restart” and then “RESTART”.
Wait for the phone to boot again. Check if the issue is gone.
In case your K51 is Frozen –
When your K51 is frozen, the power button won’t respond. In such a case, we need to force restart the phone.
As K51 comes with a non-removable battery, we cannot force power off by removing the battery. We need to use the combination of volume down & power button to do the same.
Press & hold the Volume Down & Power keys for 10 seconds or until the phone restarts.
Safe Mode
If the soft reset failed to fix your issue, use the Safe Mode before resetting the phone.
To learn how to turn on & use safe mode, please check out the below link –
How to Factory Reset LG K51 lmk500mm MetroPCS lmk500um Boost Mobile via Settings
There are 2 ways to reset an LG K51. The easier way to reset your K51 is via the Settings app.
Make sure you backup your complete LG K51 internal storage data before doing a reset.
Open “Settings” located on your K51 home screen and select “System”.
Now, Go to “Restart & reset” > “Factory data reset”
Hit “Reset phone” & finally “Delete all” to begin the factory data reset.
The process will take a few minutes and will bring you to the “Welcome” page of the Setup Wizard.
Follow the on-screen prompts and finish the setup wizard to reach the K51 home screen.
How to Hard/Master Reset LG K51 Phone without Password when Locked Out
Most of the time, the need for a factory reset arises when locked out.
If you’re locked out on your K51, the only recourse is a hard reset via Recovery mode.
I’ve forgotten the lock screen password on my K51. Let’s try to recover the phone.
To get access to the recovery mode we need to power off or restart the phone.
It’s not letting me restart/power off the phone without unlocking the screen.
The only option we have is to force restart the phone using the power & volume down button.
Press and hold the Volume Down & Power keys to restart the phone.
During the restart, when LG K51 shows up on the screen, release the power key for a moment & hold it again. Don’t leave the volume down button.
Keep holding both the keys until your phone is on the factory data reset screen.
Our K51 is in recovery mode. We need to use the volume rocker and power button in this mode.
Use the volume down button to move down from “No(Exit) to “Yes”. Select this option with the Power button.
Again move down from “No(Exit)” to “Yes” and press the power key to begin the reset process. 
The phone data is getting erased now.
We have landed on the “Welcome” page of the Setup Wizard.
Use the forward arrow to move ahead.
Setup the new second screen with or without a notch and hit “Next”.
Now, connect your K51 to the internet via Wi-Fi or Mobile data.
Hit “Don’t copy” on the “Copy apps & data” page.
Once again it’s asking for the screen lock password.
This time, there is an alternate option “USE MY GOOGLE ACCOUNT INSTEAD”. Let’s choose this option.
It brings us to the “Verify your account” screen. It’s asking for the last synced Google account on this device. If you remember the Google credentials, sign-in to your account and complete the setup wizard.
If you don’t remember the Google account details, use the following hack to get past this Google verification screen –
How to bypass Google verification on LG K1 lmk500
Tap the blank field, “Email or phone” to pull out the keyboard.
Look for the keyboard icon on the bottom-right corner and click on it.
The “Default keyboard” pop-up shows up on the screen. Select “Settings” to reach the “Manage keyboards” page.
Choose the first keyboard i.e. “Gboard”.
On the Gboard settings page, hit the “3 dots menu icon” and select “Help & feedback”.
We are now on the “Support” page.
Hit the “Describe your issue” blank field.
Type delete and select the first search result i.e. “Delete or disable apps on Android”.
Look for “Tap to go to Application Settings” and hit this option.
This brings us to the App info page.
Scroll down and select “Google” as shown above.
Now, we are on Google’s app info page –
Hit “Open” to launch the Google app.
Tap “NO THANKS” to view the Google search bar.
Type Settings and select the “Settings app with an icon” as shown above.
We are now on the Settings app.
Open “Fingerprints” and hit “Next”.
This brings us to the “Select screen lock” page.
Let’s use this to add a screen lock.
This new screen lock will replace the old screen PIN, Pattern, or Password.
I’m adding a screen PIN 1234
You can add any easy to remember screen lock.
Confirm the screen PIN.
A confirmation text shows up at the bottom of the screen “Screen lock has been changed”.
We’ve successfully replaced the old screen lock password with this new screen PIN.
Now, we need to go back to the first page of the setup wizard.
Use the back button and keep going back until you are on the “Welcome” page.
We’ve landed on the “Welcome” screen.
Use the forward button to proceed further.
Hit “Next” on the “New Second Screen” page.
This brings us to the “Copy apps & data” page. Tap “Don’t copy”.
We are now on the PIN verification page.
Here we need to enter the screen PIN we just added a few steps ago.
Enter the screen PIN 1234 and hit “OK”.
As we entered the correct screen lock PIN, there is no Google verification screen anymore.
We get the “skip” option on the Google sign-in page.
If you wish, you can add a Google account as well. The last synced account is not needed.
I’m skipping the Google account setup.
Now accept Google services terms and conditions.
Hit “OK” on the “Review additional apps” page.
And when on the “Legal documents” page, tick “I agree” and select “Done”.
This brings us to the LG K51 home screen. We have successfully performed a Hard Reset on K51 via the Recovery Mode.
If stuck at any stage, feel free to leave a comment below.