What is a bootloader on Android and how do we unlock bootloader

What is a bootloader on Android and how do we unlock bootloader 

What does a bootloader do 

Definition of bootloader  on Android Phone .

In easy words a bootloader or Hboot is security layer , which used to check and pass the Android OS before loading on your device and  make sure everything is working in order . More simple bootloader work as instructor and instruct android kernel to boot correctly. Android based on multiple partitions , some of them holding system files and other contain app data. hboot or bootloader has managerial rights to secure these partitions and scrutinize the initializing process of hardware and software as well. bootloader also prevent installation of all those software /OS which does not pass the signed test by device vendors , e.g Custom Rom's installation on Android smartphones or tablets. 

There are two kind of different bootloaders . Unlock bootloader/hboot and locked bootloader/hboot. 

Read : What is Stock ROM or  Custom ROM on Android . 

Understanding lock and unlock bootloaders.

example of locked bootloader on HTC

All and sundry know Android is an open source project therefore different manufacturers  have different kind of bootloaders depend on their requirements. Hence some smartphone shipped with lock bootloader and could be easily unlocked with single adb command " fastboot oem unlock"(for instance Google Nexus) , whereas many comes to market  locked and fully encrypted , means they are not simple to unlock with fastboot command (e.g HTC,Motorola,Sony). They allow a bit lengthy process to unlock bootloaders. Few years back these brands were too stringent about authorizing user to unlock bootloader but now they understand what android user demand. The reason behind lock bootloader is, these manufacture companies force you to stick with the Stock Firmware and official updates like OTA  and prevent you from flashing custom roms ,void warranty and huge chances of brick or dead .
Read : how to use adb commands on Android. 

How to unlock bootloader on HTC ?

If you are owner of HTC smartphone and you have decided to unlock bootloader on HTC device , you need to simply go to HTC Developer page ,sign up , select your device and follow the instructions.

How to unlock  Bootloader on Sony Xperia ?  

For unlocking bootloader on Sony Xperia smartphone or tablet visit Sony Developer page , See if your device is officially supported to unlock bootloader . Select your device and follow the instructions and enjoy different Custom ROM Flavors .

Things to remember .

Before unlocking bootloader of your android devices , keep it in mind , you cannot revert back to locked bootloader or able to restore original DRM security  keys whereas you are always capable to return on stock firmware via flashing tools.
You must backup or copy your data first. Unlocking bootloader will erase all your data hold in internal memory of your smartphone or tablet.