As stated, at the beginning of this chapter, using the serial console, we can get access to the bootloader.
Actually, the BeagleBone Black has two bootloaders: one named SPL, which is the prebootloader that initializes the hardware components, such as the RAM and some mass storage devices, and the second named U-Boot, which is the real bootloader that initializes almost all the peripherals and has support for, among other things, booting over a network, and a scriptable shell through which basic commands can be given. Now the one million dollar question is: why should a developer be able to manage the bootloader too?
Well, the answers are more than one, however, the most important are as follows: