Complete Samsung Galaxy S21 Lock Bootloader Tutorial | S21+ & Ultra too

I have the Samsung Galaxy S21 Ultra in this video and will be showing you how to lock the bootloader in a few easy steps.

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Note: Relocking the bootloader will ERASE all of your personal data. Please back up important pictures, videos (and other bits of data) ahead of time.

Requirements:

Galaxy S21 Download Mode -    • How to Boot the Galaxy S21 in & out o...  
Developer Mode -    • How to Turn On Galaxy S20 Developer M...  


We start off by booting the smartphone into Download Mode because we need to actually unlock the bootloader. Long press the Volume Up button at the splash screen to enter "unlock mode" and then confirm that you want to lock the bootloader as directed.

This will force your device to reboot and it will perform the factory data reset automatically.

It will actually reboot again after the reset has finished, and then the phone will begin to boot back into the Android OS. This first boot back into Android will take longer than normal so be patient here.

After a few minutes, you should be greeted with the Android activation screen. Go ahead and log into your accounts, make sure you have a connection to the internet (through WiFi or a mobile data SIM) and then check for an OTA update.

You can even enable Developer Mode here again if you want to disable the OEM Unlocking toggle again (which you should consider doing).

However, the toggle may not be there at first. It took me a few minutes of checking and then rebooting the phone before the toggle was revealed to me again. This is normal and nothing to get worried about.

When it appears, you can toggle it off to secure up the Galaxy S21 and complete the relock tutorial. It will then instruct you to reboot the phone one last time before using the phone like normal.


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