If you own a smartphone and are interested in tech, then it is only a matter of time before you read or hear about locked bootloaders, on how to unlock them and the fact this could void your phone's warranty. Let's get the facts straight: what is a bootloader and what is it used for?
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Let’s start from the beginning. The bootloader is a program that starts whenever a device is powered on to activate the right operating system. It is therefore not only a trait reserved to Android, but also one that can be find out all devices with an operating, be it a smartphone, a tablet, a PC etc.
It may occur that a device, a computer for example, may be equipped with two different operating systems (dual boot). In this case, either one or the other bootloader starts, depending on the user's preference or what has been pre-programmed to happen automatically.
The same principle also applies to Android devices, except that there is only one operating system in this case. The bootloader determines when to run Android or when to enter ecovery mode, which is an independent runtime environment in a partition separate from the main Android OS that can be found on all Android devices.
Manufacturers lock the bootloader of their devices so that only the operating system installed on the device can be used. Not all brand acts in the same way either: some manufacturers release their smartphones with the bootloader already unlocked (to the delight of most computer geeks).
To run a custom ROM, you need to unlock the bootloader first
Unlocking the bootloader allows you to install unauthorized software, this operation voids the warranty of your device.
The bootloader is provided directly by the manufacturer of the device and, given its importance; is found in a section of the phone's memory that can't easily be modified by the user (even though we know how much you’d like to have this freedom!). When you want to modify your own device, one of the biggest obstacles is the locked bootloader. What is involved?
A locked bootloader will only load the authorized operating systems with a digital signature. Almost every smartphone manufacturer decides to lock it by only allowing its own personalized Android to load, preventing the installation of other custom ROMs. But as you know, behind every Android problem, there is always a solution. To be able to run a custom ROMs, you first need to unlock the bootloader, which allows you to start the “unauthorized” operating system.
The method to unlock bootloaders varies per manufacturer who provide different procedures, from sending a simple command from the PC via the USB connection, to download a specific program.
Unlocking the bootloader often requires authorized root access on your device. Before taking action, secure your data by backing it up and take a look at our guides dedicated to the root:
Have you ever unlocked the bootloader of your Android? Which manufacturer do you have and how did you go about it?