Unlocking the Bootloader allows you to install custom firmware on your Android phone and gives you full access privileges to make modifications to the phone. Such modifications could involve changing some of the pre-loaded software or could even include [guide|155962|replacing the entire operating system].

Some bootloaders are not locked at all, some can be unlocked using a standard fastboot command, others need an unlock code from the manufacturer. There are also phones that do not include an unlocking method at all and can only be unlocked through a software exploit. These locked down devices will typically stem from a carrier deal.

In this guide I´ll only be covering the unlocking of bootloaders with the standard fastboot command.

== Warnings ==
* Unlocking the bootloader will reset your phone, so make sure you have all your data backed up!
* This might void your warranty with some manufacturers.
* An unlocked bootloader will trip the [link|https://developer.android.com/google/play/integrity|Play Integrity API (formerly SafetyNet Attestation API)] which can cause some services like GPay to stop working.
* This will make your device vulnerable against hackers with physical access to your device, so don´t do this to a device you intend to carry state/company secrets on.
== Additional information ==
* [link|https://en.wikipedia.org/wiki/Bootloader_unlocking|Wikipedia: Bootloader unlocking]
* [link|https://source.android.com/docs/core/bootloader/locking_unlocking|Official Android website: Locking/Unlocking the Bootloader]
* [link|https://www.xda-developers.com/|XDA developers]

Conclusie