Getting ready

We will use a Yocto toolchain to build the U-Boot source externally from the Yocto build system. The Yocto project has precompiled SDKs for both 32- and 64-bit hosts for the machines supported by Poky. You can download them from http://downloads.yoctoproject.org/releases/yocto/yocto-2.4/toolchain/.

Unfortunately, since version 2.1, it does not offer a precompiled SDK for i.MX6-based machines.

Instead, let's build an SDK using our existing Yocto Project installation:

$ cd /opt/yocto/fsl-community-bsp
$ source setup-environment wandboard
$ bitbake core-image-minimal -c populate_sdk  

We will learn more about Yocto's SDKs in Chapter 4, Application Development.

Execute the installation script from a new shell to avoid problems with the environment setup:

$ cd /opt/yocto/fsl-community-bsp/wandboard/tmp/deploy/sdk/
$ ./poky-glibc-x86_64-core-image-minimal-cortexa9hf-neon-toolchain-2.4.sh  

Accept the default installation location. It is recommended not to change the default location to avoid relocation issues.

Now we need to download the U-Boot source:

1. Find the upstream Git repository:

$ bitbake -e u-boot-fslc | grep ^SRC_URI=
SRC_URI="git://github.com/Freescale/u-boot-fslc.git;branch=2017.11+fslc file://0001-02_01-Add-a-custom-wandboard-custom-machine.patch"
  

1. Clone U-Boot's source from its upstream repository:

$ cd /opt/yocto/
$ git clone git://github.com/Freescale/u-boot-fslc.git
$ cd u-boot-fslc