Before configuring the kernel, we need to provide a default configuration for our machine, which is the one the Yocto project uses to configure a kernel. When defining a new machine in your BSP layer, you need to provide a defconfig file.
The Wandboard's defconfig file is stored under sources/meta-freescale-3rdparty/recipes-kernel/linux/linux-wandboard/defconfig.
This will be the base defconfig file for our custom hardware, so we copy it to our BSP layer:
$ cd /opt/yocto/fsl-community-bsp/sources $ mkdir -p meta-bsp-custom/recipes-kernel/linux/linux-wandboard-4.1-2.0.x/wandboard-custom/ $ cp meta-freescale-3rdparty/recipes-kernel/linux/linux-wandboard/defconfig meta-bsp-custom/recipes-kernel/linux/linux-wandboard-4.1-2.0.x/wandboard-custom/defconfig
We then add it to our kernel using meta-bsp-custom/recipes-kernel/linux/linux-wandboard_4.1-2.0.x.bbappend as follows:
FILESEXTRAPATHS_prepend := "${THISDIR}/${BP}:"
Note that the defconfig file is already part of the SRC_URI on the original recipe.
Kernel configuration changes to your platform can be made directly in this defconfig file.