nerves_bootstrap is an Elixir archive that supplies a new project generator and enhances mix to support downloading or building all of the non-Elixir things needed for Nerves-based projects. This includes crosscompilers, Linux kernels, C libraries and more.

Most users should read the Nerves Installation Guide for installing and using Nerves. Read on for details specific to nerves_bootstrap.


To install for the first time:

mix archive.install hex nerves_bootstrap

To update your nerves_bootstrap, you may either run the installation line above or:

mix local.nerves

If you need a specific version, run:

mix archive.install hex nerves_bootstrap 1.0.1

Finally, if you want to install from source:

git clone
cd nerves_bootstrap
mix do deps.get,, archive.install

Mix integration

By default, Nerves enhancements to mix are not included. This means that your non-Nerves projects will continue to build like they did before. Projects that use Nerves require additions to their mix.exs files. If you used mix to create your project, you'll already have those additions.

Nerves uses the aliases feature in mix. Ensure that the following code is in your mix.exs to pull in the integration:

  def project do
      # ...
      aliases: [loadconfig: [&bootstrap/1]],

  # Starting nerves_bootstrap pulls in the Nerves hooks to mix, but only
  # if the MIX_TARGET environment variable is set.
  defp bootstrap(args) do
    Application.start(:nerves_bootstrap)"loadconfig", args)

Mix tasks


A mix task for creating new Nerves projects.

mix my_new_nerves_project [options]

The new project's mix.exs contains logic for building any of the supported hardware systems. The customary way of selecting the specific target is to export MIX_TARGET. Here's a common build script:

export MIX_TARGET=rpi3
mix deps.get
mix firmware
mix firmware.burn

If you look at the generated mix.exs, you'll see how MIX_TARGET is used.

The generated project includes nerves_pack. This simplifies the initial configuration for many target platforms by including support for networking, firmware updates, and helpful utilities. If you want a minimal project that does not include nerves_pack, pass --no-nerves-pack:

mix my_new_nerves_project --no-nerves-pack

mix local.nerves

This task checks for updates to the nerves_bootstrap archive. If one exists, you'll be prompted to update.

mix nerves.clean

This task cleans dependencies in a similar way to mix deps.clean, but it additionally erases downloaded artifacts and build products from Nerves packages.


This task starts up a shell in an environment suitable for modifying Nerves systems. This allows you to interact with make menuconfig in Buildroot, manually enable and build C libraries, the Linux kernel, bootloaders, and more. Depending on your system, it may also start up Docker. See the Nerves documentation for usage.

Building systems and toolchains

Nerves expects systems and toolchains to include a URL to a precompiled build artifact. Building these dependencies can take hours in some cases, so Nerves will not automatically compile them. It can do this, though, and depending on your computer, it may even start up Docker to do the builds.

To force compilation to happen, add a :nerves option for the desired package in your top level project:

  {:nerves_system_rpi0, "~> 1.5", nerves: [compile: true]}