The Yocto Project uses various recipes to define interactions to each of the supported bootloaders. Since there are multiple stages of booting, there are also multiple recipes and packages required inside the BSP. The recipes available for various bootloaders are not different from any other recipes available in the Yocto world. However, they have some details that make them unique.

The board that we will focus on here is the sama5d3_xplained development board, and it is available inside the meta-atmel layer. Inside this layer, the corresponding recipes for the first and second stage bootloaders can be found inside the recipes-bsp directory. Here, I am referring to the at91bootstrap and u-boot recipes. There are some misconceptions about first stage and second stage bootloaders. They might be referred to as second level and third level bootloaders, because the boot ROM code may or may not be taken into account during a discussion. In this book, we prefer to call them as...