We have seen how to modify the Yocto build system to both modify a U-Boot or Linux kernel recipe by adding patches or by building from a modified Git repository. Now we will see how to modify and build the U-Boot source in order to introduce our changes.

Even though the Yocto Project is very flexible, it is best not to use the Yocto Project build system while developing the BSP. The U-Boot and Linux kernel binaries are separate artifacts and can be programmed individually, so it is faster and less error-prone to just build them using the standalone Yocto SDK and not the Yocto build system. This also abstracts BSP developers from the complexities of the Yocto build system.