What is BootLoader (BL)

A bootloader is a program that starts up the operating system on a computer when it is turned on. It is responsible for loading the kernel of the operating system into the computer's main memory so that the operating system can begin its operations.

The bootloader is stored in a special area of the computer's hard drive (or other storage device) that is not usually accessible by normal methods. This is to prevent accidental damage or deletion of the bootloader, which would render the computer unbootable.

In addition to loading the operating system, the bootloader also performs some basic system checks to ensure that the hardware and software are functioning correctly. If there are any problems, the bootloader can display error messages or even prevent the operating system from loading until the issue is resolved.

In the context of smartphones and other devices, a bootloader often refers to the program that starts up the device's operating system. Some devices have locked bootloaders to prevent unauthorized modifications to the operating system, while others have unlockable or already-unlocked bootloaders that allow users to install custom operating systems or ROMs.