Summary
Every system needs a bootloader to bring the hardware to life and to load a kernel. U-Boot has found favor with many developers because it supports a useful range of hardware and it is fairly easy to port to a new device. In this chapter, we learned how to inspect and drive U-Boot interactively from the command line over a serial console. These command-line exercises included loading a kernel over a network using TFTP for rapid iteration. Lastly, we learned how to port U-Boot to a new device by generating a patch for our Nova board.
Over the last few years, the complexity and ever-increasing variety of embedded hardware has led to the introduction of the device tree as a way of describing hardware. The device tree is simply a textual representation of a system that is compiled into a device tree binary (DTB), and which is passed to the kernel when it loads. It is up to the kernel to interpret the device tree and to load and initialize drivers for the devices it finds there...
