What Does Unlocking The Bootloader Do? (5 Facts To Know)

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By default, most android phones are shipped with a locked bootloader.

In simple terms, a bootloader is a piece of software that runs every time your phone starts up. It tells the phone what programs it should load to make your phone run.

It starts up the android operating system when you turn on the phone. Without a working bootloader, your phone would be a useless brick.

But at times, you may want to have complete control over what software goes on your android phone. In that case, you will want to unlock your phone’s bootloader.

What will unlocking bootloaders do Android phones?

An unlocked bootloader will give you complete autonomy over your android device. It will trigger a factory reset that will erase all of your data. It will also allow you to install a custom OS on your device. Unfortunately, it can also compromise the security of your phone and/or can brick your phone making it impossible to turn on.

When you unlock your bootloader, android wipes itself.

You will get a device with an unlocked bootloader, but one that doesn’t have any of your data in it.

You can then install a custom ROM.

It should however be mentioned that in most cases, unlocking the bootloader on your android device may make the warranty on your device void.

In this article, we are going to discuss in detail what an unlocked bootloader does, whether unlocking the bootloader deletes everything, how to unlock the bootloader, and how to know if the bootloader is unlocked or not.

So sit back, relax, and read on to find out more. This will be an insightful read!

What Does an Unlocked Bootloader Do?

As we have already mentioned, most android devices come with a locked bootloader.

And most of the carriers and manufacturers of these devices discourage people from doing this.

The truth is that unlocking the bootloader on your android device can have both positive and negative impacts.

So what are these exactly? What does unlocking the bootloader do?

1.   It gives you “Root” access

Unlocking the bootloader on your android device gives you root access.

When you root your device, you have superuser access or administrator access to the operating system that runs on your device.

Let’s take the example of Windows. When you install a new version of Windows or set up your computer for the first time, you set up the first user/administrator.

That user has access to all the bells and whistles that are behind windows- hidden files, controls panels, you name it.

A phone with root access will do the same. It allows you to access all the features that are hidden under the user interface on your device.

Rooting will give you privileges to modify the software code on your device or install other software that the manufacturer wouldn’t normally allow you to do.

2.   It erases all your data

When you unlock the bootloader on your phone, it will trigger a factory reset and android will automatically wipe itself.

All the data on your device will be deleted. You will therefore get a device with an unlocked bootloader, but one that has none of your data on it.

That’s why it’s always advisable to back up your data before unlocking.

3.   It allows you to install a custom operating system (OS) on your device

A locked bootloader means that you can’t install your own custom OS.

Unlocking the bootloader on your device will give you root access that enables you to flash the OS on your device.

After this, you will be able to install a custom OS on your device that suits all your needs.

You will be able to access any OS upgrades easily and earlier than you otherwise would.

4.   It can compromise the security

If your device has a standard locked bootloader, a thief won’t be able to get access to the device’s data without knowing the PIN or password.

If your android device’s bootloader is unlocked, the thief can reboot your device into its bootloader and boot your custom recovery mode.

From this mode, they could use the ADB command to access all the data on your device.

This bypasses any PIN or password that secures your device.

5.   It can brick your phone

Not everyone out there knows how to properly unlock the bootloader on their phone.

In most cases, if you screw something up, you could end up in a boot-loop where your device doesn’t do anything but cycle through the startup screen.

You could end up with a bricked phone that won’t turn on no matter what.

All in all, unlocking the bootloader is a job for a tech-savvy person.

If this is not your forte, it’s best not to go ahead with it.

Does Unlocking the Bootloader Delete Everything?

Yes, it does. As we have already mentioned earlier, unlocking the bootloader triggers a factory reset. This means that android will wipe itself and all your data including contacts, pictures, videos, etc. will be deleted.

This is why it’s always advisable to back up your data before unlocking the bootloader on your device.

It should however be noted that after unlocking the bootloader on your device, any data that you have on your phone from there onwards may be accessed if say a thief gets your phone.

They can then use this data against you. That’s why most manufacturers advise against unlocking the bootloader because a locked bootloader will lock out anyone who isn’t the owner.

How To Unlock Bootloader?

Unlocking the bootloader on your device is easy, especially with tools like Fastboot.

Fastboot works with a majority of android devices such as LG, Sony, HTC, Motorola, etc. Here’s how you can unlock the bootloader on your phone with Fastboot:

  • Set up ADB and Fastboot on your computer.
  • Plug your phone into your computer with its USB cable.
  • In the Command Prompt run the command “adb devices” to connect your phone. You’ll see a message requesting access on your phone. Check the box to allow the connection and confirm.
  • Run the command “adb reboot bootloader” to reboot your phone into the bootloader.
  • Wait for your phone to reboot. Now you can unlock with Fastboot. Run the command “fastboot flashing unlock”.  You may be asked to confirm, do so.

You will see a confirmation message that your bootloader has been unlocked. You can reboot your phone with Fastboot.

How To Know if the Bootloader Is Unlocked or Not?

Checking whether your phone’s bootloader is unlocked or not is easy for most android devices.

The below method should work for most devices:

  • On your device, open the phone/dialer app and enter this code *#*#7378423#*#*. (More Android code can be found here.)
  • This will open a window. Go to Service info and then Configuration. If you see a message saying “Bootloader unlock” and “Yes” written in front of it, this means that the bootloader for your phone is unlocked. If not, then your device’s bootloader is not unlocked.

In conclusion, unlocking the bootloader on your android device is a serious thing and if you do decide to go ahead with it you need to take great care. Hopefully, this guide will help you with this.


How to Geek: Security risk of unlocking your android phones

Tom’s Guide: Rooting and bootloader explanation

Android central: Bootloaders all you wanted to know

Lifewire: How to unlock bootloader android phone

Addictive tips: Check bootloader is unlocked or locked for Android