Generate multiple images at the same time in Yocto

A common task when using Yocto is to create multiple Linux images for a single target’s load. A very simple example is an emergency partition for fallback.

The easiest way is to go to your image recipe and add:

# my-image.bb
do_rootfs[depends] += "my-other-image:do_image_complete

In plain English, this means the task do_rootfs now depends on my-other-image recipe’s image_complete task. All images that inherit the image.bbclass will have the do_rootfs and do_image_complete task, so it is safe for you to depend on it.

Now every time you build your main image you also build “my-other-image“.

PS: A kind of top-level “meta” image recipe could be created that installs nothing and just depends on images so that IMAGE_CMD or wic takes the images and generates a target readable blob. Maybe one day I will post an example of such a recipe.

PSS: If your are thinking of fallback do not invent the wheel and have a look at RAUC.

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