The latest development version of this page may be more current than this released 3.1.0-0 version.

Using Zephyr without west

This page provides information on using Zephyr without west. This is not recommended for beginners due to the extra effort involved. In particular, you will have to do work “by hand” to replace these features:

  • cloning the additional source code repositories used by Zephyr in addition to the main zephyr repository, and keeping them up to date

  • specifying the locations of these repositories to the Zephyr build system

  • flashing and debugging without understanding detailed usage of the relevant host tools


If you have previously installed west and want to stop using it, uninstall it first:

pip3 uninstall west

Otherwise, Zephyr’s build system will find it and may try to use it.

Getting the Source

In addition to downloading the zephyr source code repository itself, you will need to manually clone the additional projects listed in the west manifest file inside that repository.

mkdir zephyrproject
cd zephyrproject
git clone
# clone additional repositories listed in zephyr/west.yml,
# and check out the specified revisions as well.

As you pull changes in the zephyr repository, you will also need to maintain those additional repositories, adding new ones as necessary and keeping existing ones up to date at the latest revisions.

Building applications

You can build a Zephyr application using CMake and Ninja (or make) directly without west installed if you specify any modules manually.

cmake -Bbuild -GNinja -DZEPHYR_MODULES=module1;module2;... samples/hello_world
ninja -Cbuild

When building with west installed, the Zephyr build system will use it to set ZEPHYR_MODULES.

If you don’t have west installed and your application does not need any of these repositories, the build will still work.

If you don’t have west installed and your application does need one of these repositories, you must set ZEPHYR_MODULES yourself as shown above.

See Modules (External projects) for more details.

Flashing and Debugging

Running build system targets like ninja flash, ninja debug, etc. is just a call to the corresponding west command. For example, ninja flash calls west flash1. If you don’t have west installed on your system, running those targets will fail. You can of course still flash and debug using any Flash & Debug Host Tools which work for your board (and which those west commands wrap).

If you want to use these build system targets but do not want to install west on your system using pip, it is possible to do so by manually creating a west workspace:

# cd into zephyrproject if not already there
git clone .west/west

Then create a file .west/config with the following contents:

path = zephyr

base = zephyr

After that, and in order for ninja to be able to invoke west to flash and debug, you must specify the west directory. This can be done by setting the environment variable WEST_DIR to point to zephyrproject/.west/west before running CMake to set up a build directory.



Note that west build invokes ninja, among other tools. There’s no recursive invocation of either west or ninja involved by default, however, as west build does not invoke ninja flash, debug, etc. The one exception is if you specifically run one of these build system targets with a command line like west build -t flash. In that case, west is run twice: once for west build, and in a subprocess, again for west flash. Even in this case, ninja is only run once, as ninja flash. This is because these build system targets depend on an up to date build of the Zephyr application, so it’s compiled before west flash is run.