Android from A to Z: What is the Bootloader?

We have talked a lot about what we call Root, and the importance of rooting a smartphone and unlocking the Bootloader, something essential to install the vast majority of Custom ROM. However, What is actually the Bootloader? ¿Why is it so important? What is the difference between having an unlocked Bootloader and a locked one? Are there risks in unlocking the Bootloader? Is it legal to unlock it?

What is the Bootloader?

The Bootloader is nothing other than the system's boot loader. That is, they are the first programs that are loaded on the smartphone when we turn it on. From the first program to the last there is a whole set of checks and launches of other programs. To begin with, the Bootloader is in charge of verifying that all the hardware works correctly, as well as that the operating system will be able to run without any problem. The last Bootloader program is responsible for launching the operating system, which is Android. That is the Bootloader. It is dedicated to checking that everything is correct, starting all the programs, and finally running the operating system.

Why is it so important on Android?

In Android, the Bootloader has become one of the most important elements, both for developers and for users who want to modify their smartphone. The reason is simple. The Bootloader is the one that is responsible for launching the operating system, so if we want a new operating system, or a new version, it will have to be the one to start it. The Bootloader is an essential element in any computer system, but in Android it is even more important because it is much more common to change the operating system, or the ROM. Whoever buys a Mac does not usually install Windows on it, or whoever buys a Sony Vaio, is not usually installing Linux, although it also happens. In any case, computers are prepared to be able to install other operating systems, but smartphones usually have the Bootloader blocked.

Why does the Bootloader hang?

The Bootloader is blocked for a single reason, to prevent users from having power over the terminal. Manufacturing companies usually block the Bootloader so that users have to use its interface and software. Operators often want to lock the Bootloader to prevent software from being installed that could unlock the smartphone, thus preventing it from being used with another operator.

What is achieved by unlocking the Bootloader?

The million dollar question is why would I want to unlock the Bootloader. The answer is two million, not just one. Because a smartphone changes radically. The difference between using the interface of Samsung, Sony, LG, HTC, and that of a highly optimized Custom ROM is immense. While the former slow down the system, the latter makes the smartphone fly, and without exaggeration. Unlocking the Bootloader we can install other operating systems, or other versions of the same operating system. That block that prevented modifying the system that was being started, ceases to exist. In addition, we can also make modifications to the operation of the hardware, making a processor work at higher performance.

How do you unlock the Bootloader?

The Bootloader is unlocked by means of exploits, that is, by means of programs that take advantage of security errors to obtain the necessary privileges within the system that allow them to modify the Bootloader, and unlock it. Security errors, in quotes. Companies cannot legally lock the Bootloader, and therefore often leave "bugs", ways to unlock the Bootloader. Only level developers, and those users willing to trust them, unlock the Bootloader. Meanwhile, the vast majority of Android's do not have an unlocked Bootloader.

Thus, if you want to unlock the Bootloader, you have to look for the exploit that a developer has created for that particular smartphone with that version of the operating system. If the smartphone is very new, and very famous, it will be worth following the news of the specialized blogs.

Are there risks when unlocking the Bootloader?

Now, can something happen to the smartphone when unlocking the Bootloader? It could be dangerous. The developers take advantage of an error, which in many cases is there precisely by the companies, and in such cases there is no danger. However, sometimes it is an error that is not the fault of the companies, and in those cases, our smartphone could die. On the other hand, it must be taken into account that there are several versions of each smartphone, with slight variations and that what is compatible with one is not compatible with another. In the end, the most normal thing is that if many users have unlocked the Bootloader with a procedure, this is not dangerous.

In addition, the Bootloader allows us to make modifications on the terminal, on the operation of the hardware, such as the speed at which the processor computes. This can cause the processor itself to stop working, or a component of the terminal to be damaged. Therefore, if we unlock the Bootloader, we lose the warranty.

Is it legal to unlock the Bootloader?

Legal yes it is. What is illegal? To give us an idea. Jailbreaking an iPhone is legal. However, it becomes illegal when after jailbreaking we continue to use iOS as the operating system. Why? We have paid for the terminal, but not for the software, which is a concession that Apple makes us when buying the smartphone. If we accept the terms of use of the Apple operating system, then we agree not to jailbreak. If we jailbreak, then we are in breach of those conditions, and we must stop using the software. What happens on Android? The Bootloader must be able to be unlocked. The reason why it is blocked is so that we do not change the operating system for another. Obviously, if we unlock it, it is to replace the operating system, because if not, it would not make sense in many cases. In any case, some companies even indicate the procedure to unlock the smartphone's Bootloader, or Google itself sells terminals with an unlocked Bootloader. It is a clear proof that on Android it is not illegal to do so, nor to use the software.