Building Embedded Linux Systems

Chapter 9. Setting Up the Bootloader

Though the bootloader runs for a very short time during the system’s startup and is mainly responsible for loading the kernel, it is a very important system component. Setting up a bootloader is, to some extent, a task common to all Linux systems. It is a special task, nevertheless, for embedded Linux systems, because the bootloaders used in such systems are either completely different from those used in common systems or, even when they are the same, are configured and operated in very different ways.

Chapter 7 discussed the manipulation of embedded storage devices, and Chapter 8 explained how to set up a root filesystem for use in an embedded target. We are now ready to set up the bootloader along with the other components created earlier so we may obtain a bootable and functional embedded system. Because hardware architectures differ greatly among each other and because boards based on the same architecture differ greatly among themselves, the selection, set up, and configuration of a bootloader depend largely on the hardware you are using.

There is a slew of bootloaders available for Linux, thousands upon thousands of embedded boards, and many possible boot configurations for a same board. It is, therefore, inconceivable to cover all the possible combinations within a single chapter. Nor is it possible to give an in-depth discussion of the use of each of the bootloaders covered. Many existing bootloaders for Linux either already have an entire ...