# Changelog

## v1.10.4 - 2023-09-13

* Improvements
  * Adjust compilation error when `nerves_bootstrap` is missing

* Bug Fix
  * Adjust `mix` for OTP 26
    * With OTP 26, this task cannot completely handle the shell and
      instead prints out the command to run manually for the
      same effect.

## v1.10.3 - 2023-07-07

* Improvements
  * Support Elixir 1.15 / OTP 26
  * Fix misleading `%IO.Stream{}` error when building firmware
  * Add validations for `vm.args.eex` during firmware build

## v1.10.2 - 2023-04-11

* Improvements
  * Change `BuildRunners.Docker` to use GitHub Container Registry by default

## v1.10.1 - 2023-03-08

* Improvements
  * Use `GitHubAPI` for public release artifacts for helpful reports on error
  * Allow `castore: v1.0` to be used

## v1.10.0 - 2023-03-03

This release removes the ability to specify an alternative JSON codec with
`:json_codec` config option and defaults to using `Jason`. If set, everything
will function as normal but you will see a compiler warning.

* Bug fix
  * Prevent accidentally installing `:nerves` as an archive
  * Add default mksquashfs flags when none specified

## v1.9.3 - 2023-02-11

* Bug fix
  * Temporarily revert GitHub release update in v1.9.2. It produces an error on
    new projects when downloading artifacts. It's easily fixed by adding a
    `jason`, but a better fix will be coming.

## v1.9.2 - 2023-02-05

* Improvements
  * `:github_api` artifact site resolver was completely refactored
    * More contextual error messages
    * `GITHUB_TOKEN` and `GH_TOKEN` environment variables supported (They were
      previously ignored despite the error message suggesting them to be used)
    * `:user` option no longer required, but still supported (effectively ignored
      by GitHub if the token is supplied)
  * `:github_release` switched to use the same GitHub resolver as `:github_api`
    in order to have the same benefits
  * Remove duplicate artifact request with 64 byte checksum name

* Bug Fix
  * `mix firmware` now places temporary build products in `MIX_BUILD_PATH` which
    prevents them from being stored in `_build/` root and compiling different
    targets in different terminals. See #576
  * Check if supplied rootfs_overlays have incompatible directories. See

## v1.9.1 - 2022-09-11

This is a patch release that fixes trivial tooling issues found when using
Elixir 1.14 and Erlang 25.0.4. It's expected to be a safe update from v1.9.0.

## v1.9.0 - 2022-08-23

This release removes warnings when using Elixir 1.14 rc releases since they
appear to work fine.

* Improvements
  * Added `mix nerves.artifact.details` to list information in Nerves system and
    toolchain projects. Thanks to @udoschneider for this feature.
  * Many documentation updates including version charts for Nerves systems.
    Thanks to @mnishiguchi.

## v1.8.0 - 2022-05-11

This release requires Elixir 1.11.2 or later. It has no new features. This is
the first batch of updates to improve our ability to maintain Nerves tooling
long term now that we can remove old features and workaround.

* Bug fix
  * Fix missing space in `CFLAGS` and `CXXFLAGS`. It would sometimes cause
    compiler warnings.

## v1.7.16

* Bug fix
  * Fix Erlang compiler check so that Erlang/OTP 24.3 does not trigger an error
    when building projects.

## v1.7.15

* Bug fix
  * Fix `TARGET_GCC_FLAGS` issue that inadvertently removed `CFLAGS` options on
    Nerves systems that used it.

## v1.7.14

* Improvements
  * Unset environment variables set by Erlang that can confuse some C/C++
    libraries when building.
  * Add experimental support for `TARGET_GCC_FLAGS` for enabling CPU-specific
    features in NIFs and ports via Nerves package definitions. This is similar
    in intent to `TARGET_CPU`, etc.

## v1.7.13

* Improvements
  * Verify the remote website when downloading artifacts. This fixes the warning
    about unverified HTTPS connections.
  * Fix error message printout when Nerves toolchain builds fail

## v1.7.12

* Improvements
  * Allow Elixir 1.13.0-rc.0 to be used to build projects. It looks like it
    works fine and doesn't cause issues with Nerves.
  * Add message after the build completes to let you know what to do next.

## v1.7.11

* Bug fixes
  * Don't set xattrs when running `mix firmware.unpack`. This fixes filesystem
    permission errors during extraction for some users.

## v1.7.10

* Improvements
  * Update `mix firmware.unpack` to be more flexible with input firmware and
    output directories. If you're using `mix firmware.unpack` in a script, you
    may need to update the script.
  * Reduce C compiler build prints

## v1.7.9

* Improvements
  * Add helper script generator for using gdb to analyze core dumps. Nerves
    systems ship with debug symbols (target images have these stripped) that can
    be used to get stack traces and more from core dumps from the Erlang VM and
    other C/C++ programs. See the [Debugging C in Nerves blog
    post]( for an example.
  * Support the new `:limits` option in erlinit so that it's possible to set the
    core dump limits (i.e., enable core dumps) before Erlang starts.

## v1.7.8

* Bug fixes
  * Fix toolchain downloads when using Erlang/OTP 24 on Apple M1 macs.

## v1.7.7

* Bug fixes
  * Fix compiler version check error when using Erlang/OTP 24

## v1.7.6

* Enhancements
  * Update supported Elixir version to include 1.12

## v1.7.5

* Bug fixes
  * Fixes an issue where query parameters would be percent-encoded twice.
    Packages that use `query_params` argument option to `artifact_sites` could
    be impacted. For example, packages storing build artifacts in AWS S3
    require the `X-Amz-Credential` query parameter key whose value
    includes the reserved character `/`. This symbol is double encoded to
    `%252F`. This failed on systems with Erlang OTP-23.2 and above.
    See for additional context.

## v1.7.4

* Experimental features
  * Packages can provide custom system environment variables to be exported.
    The initial use case for this feature is to export system specific
    information for llvm-based tools.

## v1.7.3

* Bug fixes
  * Fixes a hang when downloading artifacts from GitHub. The hang looked like
    this and affected artifact downloads from public GitHub repositories:

    Resolving Nerves artifacts...
      Resolving nerves_toolchain_xyz
      => Trying https:...

## v1.7.2

* Bug fixes
  * Fix Elixir semver requirements to produce warnings on unsupported versions.
  * Produce better errors on HTTP timeouts

## v1.7.1

* Enhancements
  * Documentation and docker improvements for Windows Subsystem for Linux 2

## v1.7.0

Nerves 1.7.0 removes support for creating OTP releases using Distillery and
only supports using Elixir releases. As a result, the minimum supported version
of Elixir is now version 1.9.

Official Nerves systems now support applying firmware using patches. This
greatly reduces the amount of data that required to push firmware updates
to devices. The minimum requirement for fwup has been updated to 1.8
to enable support for this feature.

* Bug fixes
  * Pass all unspecified erlinit args to the generator instead of silently
    ignoring them.
  * Use host CC when compiling the port.

## v1.6.5

* Bug fixes
  * Fix issues with executing system commands on non mac hosts.

## v1.6.4

* Experimental features
  * Added `mix firmware.patch` to locally create firmware patch files for
    feature testing. This feature is under development.
    See the [experimental features]( doc for more info.
  * Added `:mksquashfs_flags` to the nerves firmware config to allow passing
    additional flags to the `mksquashfs` call that produces the final rootfs.
    If you are experimenting with creating patchable firmware, you should
    use this feature to disable squashfs compression.

    config :nerves, :firmware
      mksquashfs_flags: ["-noI", "-noD", "-noF", "-noX"]

* Bug fixes
  * Replace calls to `System.cmd` with a `Nerves.Port.cmd`. This code was
    provided by `muontrap` and is used to clean up spawned system processes
    when the vm exits.
    This fixes issues with the docker build runner executing multiple times
    and multiple calls to `mix firmware` after breaking out of the VM before
    the first call finishes.
  * Fix issue where SD card detection may fail while calling `mix burn` when`fwup`
    returns additional fields.
  * Clean the release directory when calling `mix firmware`. This prevents
    OTP releases from accumulating unnecessary libraries and OTP applications
    over time.

## v1.6.3

* Bug fixes
  * Fix required key validation on github_api resolver.

## v1.6.2

* Bug fixes
  * Improve error message returned when calling `mix firmware` when the local
    system artifact cannot be found and possibly needs to be built.

  * GitHub API artifact resolver will no longer raise if missing required opts.

  The GitHub API artifact resolver is useful when you want to enable access
  to artifacts added to GitHub releases in private GitHub repositories.
  Fetching an artifact from a private GitHub repo requires the passing
  `username, token, tag` as options. If any of these options were omitted,
  the resolver would raise and prevent compilation from continuing.
  This is problematic when you are trying to actually compile the system
  in CI. Artifact resolvers should make a best effort on downloading the
  artifacts, and return `{:error, reason}` if they are unsuccessful. This
  will allow the system to fall back to performing a compile.

## v1.6.1

* Enhancements
  * Updated documentation to reflect changes in [`nerves_bootstrap 1.8`](
    Updates references to `nerves_init_gadget` and replace with `nerves_pack`.
    This change shifts new projects and main documentation to promote the use of
    [`vintage_net`]( for device networking.
  * Bump the host installed `fwup` version requirement to `~> 1.5`.

## v1.6.0

Nerves 1.6.0 adds support for Elixir 1.10.

As part of the update to Elixir 1.10, it became more difficult to support old
Elixir and Erlang versions. Therefore, Nerves 1.6.0 requires at least Elixir
v1.7.0 and Erlang/OTP 21. If your project requires an older version of Elixir or
Erlang/OTP you can pin the version of `nerves` to an older version.

For example, set your nerves dependency in your mix.exs to:

{:nerves, "~> 1.5.0", runtime: false},

* Enhancements
  * Add support for aarch64 host architecture.
  * Add `mix firmware.metadata` for listing firmware metadata values.

## v1.5.4

* Enhancements
  * Add `mix firmware.unpack` to unpack generated `.fw` files. This is useful
    to inspect the contents of the target root filesystem and other .fw info
    on the host.
  * Update `mix burn` to accept the path to a `.fw` file with `--firmware | -i`.

* Bug fixes
  * Invoke `mix firmware` when calling `mix firmware.image`. This matches the
    behavior of `mix firmware.burn`.
  * Fix issue with artifact base_dir expansion. This fixes an issue where mix
    would attempt to resolve the nerves dependency artifacts even though they
    have already been downloaded.
  * Always generate `erlinit.config`, even if there are no config override in
    mix config. This fixes an issue where removing overrides from mix config
    would not update the erlinit.config.

## v1.5.3

* Bug fixes
  * Fix various erlinit option parsing/formatting issues.

## v1.5.2

* Enhancements
  * erlinit.config options can be overridden using the application config now.
    For example, in your config.exs you can now add:

    config :nerves, :erlinit,
      ctty: "ttyAMA0"

  * Nerves tooling now supports setting the SOURCE_DATE_EPOCH environment
    variable for reproducible builds during compilation via `:source_date_epoch`
    in your application config. This removes timestamp differences between
    builds. See []( for more information.
  * Windows Subsystem for Linux improvements
  * Support XDG_DATA_HOME. If XDG_DATA_HOME is set, Nerves will now store its
    data under that directory.

* Bug fixes
  * Do not require sudo on `mix burn` if already privileged.
  * Keep all boot scripts. Previously, extraneous boot scripts from the OTP
    release process were removed. Keeping them makes it possible to start
    Erlang slave nodes and support use cases where triggers at device boot
    time launch different scripts.

## v1.5.1

* Bug fixes
  * Update compiler check on `mix firmware` to use the system OTP version
    when recommending an Elixir install.
  * Check if using Distillery when calling `mix nerves.release.init`.
    This is no longer required for Elixir 1.9+ releases.

## v1.5.0

**Updating to Nerves v1.5.0 requires modifications to your project**
See the [project update guide]( to learn how to migrate your project.

* Enhancements
  * Added support for Elixir 1.9+ releases.

* Bug fixes
  * Do not include empty priv directories when constructing rootfs

## v1.4.5

* Enhancements
  * Updated docs.

* Bug fixes
  * Updated the requirement for `distillery` to `~> 2.0.12`. This fixes an issue
    where `nerves` would downgrade to `1.4.0` when updating `shoehorn`.
  * Empty `priv` directories are not added to the squashfs sort ordering list.

## v1.4.4

* Bug fixes
  * This improves the path fix in v1.4.3 (see to cover the local
    build runner as well.

## v1.4.3

* Bug fixes
  * Raise an exception if the artifact cache fails to create a directory
  * Fixes `ArgumentError` when using OTP >= 21.3.0 and calling `mix`
  * Fixes issue with `mix` using `asdf` >= 0.7.0 where the
    path would contain `::` and Buildroot would raise the error:

    You seem to have the current working directory in your
    PATH environment variable. This doesn't work.
    support/dependencies/ recipe for target 'dependencies' failed

## v1.4.2

* Improvements
  * Generate rootfs.priorities file. This is used internally when constructing
    the squashfs filesystem to arrange the contents in the order the files are
    loaded at runtime which improves boot performance.

## v1.4.1

* Improvements
  * Improve error message when artifacts can't be found

## v1.4.0

Version v1.4.0 adds support for Elixir 1.8's new built-in support for mix
targets. In Nerves, the `MIX_TARGET` was used to select the appropriate set of
dependencies for a device. This lets you switch between building for different
boards and your host. Elixir 1.8 pulls this support into `mix` and lets you
annotate dependencies for which targets they should be used.

See the [project update guide]( to learn how to migrate your project.

## v1.3.4

* Bug fixes
  * Fixed issue where specifying `build_runner_opts` without `build_runner`
    would prevent `build_runner_opts` from being set.
  * Allow `http_opts` to be merged in from the artifact site opts. This fixes
    an issue with downloading artifacts from github enterprise by specifying
    `[autoredirect: true]` in the artifact site opts.

## v1.3.3

* Bug fixes
  * Lock dependency on distillery to `2.0.10` to work around:

## v1.3.2

* Bug fixes
  * Improved handling for burning firmware with Windows Subsystem for Linux.
  * `mix nerves.deps.get` will raise if a download was incomplete or corrupt
    after trying all resolvers.
  * `mix firmware.burn` will call `mix firmware` to ensure the firmware is the
  * `mix burn` was added to allow for burning the latest built firmware without
    calling `mix firmware`.

## v1.3.1

* Bug fixes
  * Fix `fwup` invocations for NixOS users
  * Add `--verbose` option on `mix firmware` to help debug OTP release
  * Force users to run Elixir 1.7.3 or later if using Elixir 1.7. This avoids
    a known issue in Elixir 1.7.2 and Distillery 2.0.
  * Remove unused cookies in default `rel/config.exs` files

## v1.3.0

This version adds support for Elixir ~> 1.7 which requires updates to your
Mix project.

**Modify the release config**

It is required to modify the `rel/config.exs` file.

Change this:

release :my_app do
  set version: current_version(:my_app)
  plugin Shoehorn
  if System.get_env("NERVES_SYSTEM") do
    set dev_mode: false
    set include_src: false
    set include_erts: System.get_env("ERL_LIB_DIR")
    set include_system_libs: System.get_env("ERL_SYSTEM_LIB_DIR")
    set vm_args: "rel/vm.args"

To this:

release :my_app do
  set version: current_version(:my_app)
  plugin Shoehorn
  plugin Nerves

**Update shoehorn**

You will need to update your version of shoehorn to `{:shoehorn, "~> 0.4"}`.

## v1.2.1

* Enhancements
  * Update minimum required version for fwup to at least 1.2.5

## v1.2.0

* Enhancements
  * Added ability to override provisioning.conf in the project mix config.
    This can be done by setting the key `provisioning`.


      config :nerves, :firmware,
        provisioning: "config/provisioning.conf"

      # or delegate it to an app that sets nerves_provisioning: "path/to/file"

      config :nerves, :firmware,
        provisioning: :nerves_hub

  * Bug Fixes
    * Fix issue with setting provisioning environment variables when calling
      `mix firmware.burn` on Linux systems. Environment variables prefixed with
      `NERVES_` and the variable `SERIAL_NUMBER` will be copied into the environment.

## v1.1.1

* Enhancements
  * Updated docs to bump required versions of tools.

* Bug Fixes
  * Docker build runner
    * Use the version of the `nerves_system_br` as the tag for the docker image
      to pull by default.
    * Create and set the user id and group id in the docker entrypoint.
      This fixes issues with building buildroot packages that require
      access to the users home folder.

## v1.1.0

* Enhancements
  * `mix firmware.burn` can run within Windows Subsystem for Linux
  * Added `make_args` to `build_runner_opts`

  For example:

    You can configure the number of parallel jobs that buildroot
    can use for execution. This is useful for situations where you may
    have a machine with a lot of CPUs but not enough ram.

      # mix.exs
      defp nerves_package do
          # ...
          build_runner_opts: [make_args: ["PARALLEL_JOBS=8"]],

## v1.0.1

* Enhancements
  * General documentation updates.
* Bug fixes
  * Do not fetch artifacts on deps.get if they are overridden using environment
    variables like `NERVES_SYSTEM=/path/to/system`.

## v1.0.0

* Bug Fixes
  * `Nerves.Artifact.BuildRunners.Docker` was running as root and caused file
    permission issues with the `deps` directory of the root `mix` project.
    The `Docker` build runner now executes as the same user id and group id as
    the host.

## v1.0.0-rc.2

This version renames the module `Nerves.Artifact.Provider` to
`Nerves.Artifact.BuildRunner`. This change should only affect custom systems
and host tools that override the defaults in `nerves_package` config.

* Enhancements
  * Allow specifying multiple rootfs_overlay directories in the config.
  * Automatically remove corrupt files from the download directory.
  * Updated System documentation.
* Bug Fixes
  * Check the download directory before attempting to download the artifact.
  * Changed the host tool check to use `System.find_executable("command")` instead of
    calling out to `System.cmd("which", ["command"])`. This addressed an issue with
    NodeJS breaking anything that called into `which` resulting in an obscure error.

## v1.0.0-rc.1

This rc contains documentation cleanup and updates through out.

* Enhancements
  * Support forwarding the ssh-agent through Docker for the Nerves system shell.
  * Allow headers and query params to be passed to the `:prefix` `artifact_sites`

    `{:prefix, "", headers: [{"Authorization", "Basic 1234"}]}`
    `{:prefix, "", query_params: %{"id" => "1234"}}`

  * Added `github_api`to `artifact_sites` for accessing release artifacts on private
    github repositories.

    `{:github_api, "owner/repo", username: "skroob", token: "1234567", tag: "v0.1.0"}`

* Bug Fixes
  * Disable the nerves_package compiler if the `NERVES_ENV_DISABLED` is set.
    This makes it easier to execute `mix` tasks without building the system.

    `NERVES_ENV_DISABLED=1 mix docs`

## v1.0.0-rc.0

Nerves no longer automatically compiles any `nerves_package` that is missing its
pre-compiled artifact. This turned out to rarely be desired and caused
unexpectedly long compilation times when things like the Linux kernel or gcc got

When a pre-compiled artifact is missing, Nerves will now tell you what your
options are to resolve this. It could be retrying `mix deps.get` to download it
again. If you want to force compilation to happen, add a `:nerves` option for
the desired package in your top level project:

  {:nerves_system_rpi0, "~> 1.0-rc", nerves: [compile: true]}

* Bug Fixes
  * Mix raises a more informative error if the `nerves_package` compiler
    attempts to run and the `nerves_bootstrap` application has not been
    started.  This also produces more informative errors when trying to
    compile from the top of an umbrella.

## v0.11.0

* Bug Fixes
  * Including the entire artifact checksum in artifact download file name was causing issues with
    file encryption libraries. Fixed by changing the artifact download name to only
    use the first 7 of the artifact checksum.

## v0.10.1

* Bug Fixes
  * Ensure the artifact cache dir is clean and created before putting artifacts.

## v0.10.0

* Enhancements
  * Call `bootstrap/1` on any package that defines a platform
  * Added Nerves.Utils.File.tar helper for creating archives
  * Only apply the host tuple `portable` to packages with type `system`
  * Packages other then toolchains and systems can override their artifact
    paths using an env var of their app name. For example. a package called
    `:host_tool` would be able to override the artifact path by setting
    `HOST_TOOL` in the environment.
  * Allow any package that declares a provider to create an artifact.
  * Fixed up test fixtures and added integration test.

* Bug Fixes
  * Do not raise when trying to make a directory when putting an artifact in
    the global cache.
  * Ensure the Nerves environment has been started when calling `nerves

## v0.9.4

* Bug Fixes
  * Fix artifact archiver to use `Artifact.download_name/1` instead of
    ``. Fixes issues with the Docker provider and
    `mix nerves.artifact`
  * Fix issue with `` not rendering properly

## v0.9.3

* Bug Fixes
  * Artifact download_path should use download_name. This was causing a
    mismatch between dl files from buildroot and the resolver causing it to
    have to download them twice
  * Fixed issue with compiling certain nerves packages when calling
    `mix deps.compile`

## v0.9.2

* Bug Fixes
  * Fixed issue where env var artifact path overides were being calculated
    instead of honored.

## v0.9.1

* Bug Fixes
  * Fixed issue with artifact default path containing duplicate names
  * `Nerves.Env.host_os` can be set from `$HOST_OS` for use with canadian
    cross compile
  * `Nerves.Env.host_arch` can be set from `$HOST_ARCH` for use with canadian
    cross compile
  * mkdir -p on `Artifact.base_dir` before trying to link to build path
  * raise if artifact_urls are not binaries.

## v0.9.0

* Update Notes

Starting in Nerves v0.9.0, artifacts will no longer be fetched during `mix
compile`. Artifact archives are intended to be fetched following `mix deps.get`.
To handle this, you will need to update your installed version of
`nerves_bootstrap` by calling `mix nerves.local`. After updating
`nerves_bootstrap`, you should update your `mix.exs` file to add the new
required mix aliases found there. A helper function is available named
`Nerves.Bootstrap.add_aliases` that you can pipe your existing aliases to like

  defp aliases(_target) do
      # Add custom mix aliases here
    |> Nerves.Bootstrap.add_aliases()

Also, update your nerves dependency to:

`{:nerves, "~> 0.9", runtime: false}`

* API Changes
  * Moved `Nerves.Package.Providers` to `Nerves.Artifact.Providers`
  * Moved `Nerves.Package.Providers.HTTP` to `Nerves.Artifact.Resolver`
  * `Nerves.Artifact.Resolver` no longer implements the
    `Nerves.Artifact.Provider` behaviour.

* Enhancements
  * Added Mix task `nerves.artifact.get`. Use to fetch the artifact archive from an
    `artifact_url` location. Once downloaded its checksum will be checked against
    `artifact_checksum` from the `nerves_package` config in `mix.exs`. The Mix task
    `nerves.deps.get` will recursively call `nerves.artifact.get` to fetch archives.
  * Added Mix task `nerves.artifact`. This task will produce the
    artifact archive file which are used when calling `nerves.artifact.get`.
  * Nerves packages can override the Provider in the `nerves_package` config
    in `mix.exs` using the keys `provider` and `provider_opts`. This is
    useful to force a package to build using a specific provider like
    `Nerves.Artifact.Providers.Docker`. See the [package configuration docs](
    for more information.
  * Added `artifact_sites` to the `nerves_package` config. Artifact sites
    are helpers that are useful for cleanly specifying locations where artifacts
    can be fetched. If you are hosting your artifacts using Github releases
    you can specify it like this:

    artifact_sites: [
      {:github_releases, "organization/project"}

    You can also specify your own custom server location by using the `:prefix`
    helper by passing a url or file path:

    artifact_sites: [
      {:prefix, "/path/to/artifacts"}
      {:prefix, ""}

    Artifact sites will be tried in order until one successfully downloads the
* Bug Fixes
  * Fixed issue with `Nerves.Utils.HTTPResolver` crashing when missing the
    `content-disposition` and `content-length` headers.
  * Run integrity check on tar files to validate they are not corrupted on

## v0.8.3

* Bug Fixes
  * Revert plugin Nerves in new project generator until
    the fix can be made in distillery.
    This issue was causing the release to contain compiled
    libraries from the host instead of the target.
    The error would look similar to this

    ELF 64-bit LSB relocatable, x86-64, version 1

    If binary, expecting:
    ELF 32-bit LSB executable, ARM, EABI5 version 1, interpreter /lib/, for GNU/Linux 4.1.39

    You can fix this by updating and regenerating the new project.

## v0.8.2

* Enhancements
  * Added [contributing guide](
  * Improved error messages when `NERVES_SYSTEM` or `NERVES_TOOLCHAIN` are unset.

* Bug Fixes
  * Don't override the output_dir in the Distillery Plugin.

## v0.8.1

* Bug Fixes
  * Fixed an error in the `Nerves` Distillery plugin that was causing the following error message:

    Plugin failed: no function clause matching in IO.chardata_to_string/1

## v0.8.0

* Enhancements
  * Removed legacy compiler key from the package struct. The `nerves_package` compiler will be chosen by default.
  * Simplified the distillery release config by making Nerves a distillery plugin
  * Skip archival phase when making firmware.
  * Allow the progress bar to be disabled for use in CI systems by setting `NERVES_LOG_DISABLE_PROGRESS_BAR=1`
  * Deprecate nerves.exs. The contents of nerves.exs files have been moved into mix.exs under the project key `nerves_package`

* Bug Fixes
  * raise an exception when the artifact build encounters an error

## v0.7.5

* Enhancements
  * Docker
    * Reduced the image size by optimizing docker file.
    * Images are pulled from Docker Hub instead of building locally.
    * Containers are transient and build files are stored in docker volumes.
    * NERVES_BR_DL_DIR is mounted as a host volume instead of a docker volume.

* Bug Fixes
  * Docker
    * Fixed issue where moving the project location on the host would require
      the container to be force deleted.

## v0.7.4

* Bug Fixes
  * Make sure the path NERVES_DL_DIR exists before writing artifacts to it.

## v0.7.3

* Enhancements
  * [mix firmware.image] remove the need to pass an image name. Default to the app name.
  * [mix] added shortdocs to all mix tasks.
  * [fwup] bumped requirement to ~> 0.15 and support 1.0.0 pre release.
  * Cache downloads to ~/.nerves/dl or $NERVES_DL_DIR if defined.

## v0.7.2

* Bug Fixes
  * Fixed issue where `` would hang and load improperly.
* Enhancements
  * Deprecated the `rootfs_additions` configuration option, to be superseded by
    the `rootfs_overlay` option, which matches the convention used by the
    Buildroot community.

## v0.7.1

* Bug Fixes
  * The `` Mix task should not do `make clean` by default.
* Enhancements
  * The "Customizing Your Own Nerves System" documentation has been updated to
    include the `mix` functionality, including a blurb to
    recommend running a clean build any time it's not working as expected.

## 0.7.0

* Bug Fixes
  * Try to include the parent project when loading Nerves packages
  * Better error message from the Docker provider when Docker is not installed
  * Delete system artifact directories only when instructed by `mix nerves.clean` on Linux.
    This prevents triggering a full rebuild for every change made to a custom system.
* Enhancements
  * Added support for the new `` task, provided by
    `nerves_bootstrap`, to `Nerves.Package.Providers.Docker` and
    `Nerves.Package.Providers.Local`, which provides a consistent way to
    configure a Buildroot-based Nerves system on both OSX and Linux. This
    replaces the `` Mix task, which had not been fully implemented.
  * `mix firmware.burn` no longer asks for your password if using Linux and have
     read/write permissions on the SD card device.

## 0.6.1

* Bug Fixes
  * Docker Provider: Fix version parsing issue when major, minor, or patch contains leading zeros.

## 0.6.0

* Bug Fixes
  * Require Nerves Packages to have a version
* Enhancements
  * Propagate Mix.Project.config settings into the firmware metadata
  * Removed checksum from docker container name. Docker provider now only builds changes
  * Added Nerves.Env.clean for cleaning package providers

## 0.5.2

* BugFixes
  * Handle redirects manually as a fix to OTP 19.3 caused by [ERL-316](

## 0.5.1

* BugFixes
  * Handle redirects manually as a fix to OTP 19.3 caused by [ERL-316](

## 0.5.0

* Bug Fixes
  * `:nocache` the HTTP provider if the download list is empty
  * return an error when tar is unsuccessful at decompressing an artifact
  * return `:error` for any error in downloading artifacts
  * clean up temp files after downloading artifacts
  * expand path before comparing for dep type: Fixes path deps in umbrella
  * clean up artifact dir before copying new artifact
* Enhancements
  * changed console output for higher visibility Nerves compiler messages
  * added ability to specify the images_path in the Mix.Project config
  * changed default images_path to `#{build_path}/nerves/images`
  * updated docs to reflect changes made to project structure
  * added `mix` task. Can be used to gain information about the Nerves env

## 0.4.8

* Bug Fixes
  * removed `--silent` from `mix release.clean` for compatibility with `:distillery ~> 1.2.0`

## 0.4.7

* Bug Fixes
  * [Providers.Local] Fix return error on non zero exit status code
  * Fixed IO stream split to handle ANSI code case regression

## 0.4.6

* Bug Fixes
  * fix artifact http download manager to take as long as it needs unless idle for more than 2 minutes.
  * [Providers.Docker] Fixed IO stream parsing to handle occasions where ANSI codes are not being passed.
  * loosened dependency on distillery

## 0.4.5

* Bug Fixes
  * catch exits from mix release.clean when calling mix firmware

## 0.4.4

* Bug Fixes
  * return an `{:error, message}` response from the http provider when a resource is not found

## 0.4.3

* Enhancements
  * Mix will display a progress bar, percentage, and total / expected bytes when downloading artifacts.
  * Added task `mix firmware.image my_app.img` for producing images for use with applications like dd
  * Silenced output from distillery which would contain misleading information for the nerves project

* Bug Fixes
  * Docker provider could potentially produce application id's that were invalid

## 0.4.2

* Bug Fixes
  * Fixed issue where artifact paths could not be set by system env var
  * Mix Task `nerves.release.init` was failing due to missing template. Include priv in hex package files.

## 0.4.1

* Bug Fixes
  * Do not stop the Nerves.Env at the end of the package compiler. This would cause the packages to resolve the wrong dep type.
  * Fixed issue where remote artifacts would not be globally cached
  * Fixed issue with package compiler where it would always force systems to be built

## 0.4.0

* Enhancements
  * Improved test suite
  * Added documentation for modules
  * Consolidated the Nerves Environment to the Nerves package

## 0.4.0-rc.0

* Enhancements
  * Consolidated compilers into `nerves_package`.
  * Removed dependency for `nerves_system`
  * Removed dependency for `nerves_toolchain`
  * Added Docker provider for building custom systems on machines other than linux

## 0.3.4

* Bug Fixes
  * Fixed regression with `mix firmware.burn` to allow prompts
* Enhancements
  * Added ability to override task in `mix firmware.burn`. You can now pass `-t` or `--task` to perform `upgrade` or anything else. Default is `complete`

## 0.3.3

* Bug Fixes
  * Updated nerves.precompile / loadpaths to support Elixir 1.3.x aliases.
* Enhancements
  * Removed dependency on porcelain

## 0.3.2

* Bug Fixes
  * Support for elixir 1.3.0-dev
  * Invoke `nerves.loadpaths` on preflight of `mix firmware` and `mix firmware.burn`. Fixes `ERROR: It looks like the system hasn't been built!`

## 0.3.1

* Enhancements
  * Perform host tool checks before executing scripts

## 0.3.0

* Enhancements
  * Added nerves_bootstrap archive
  * `mix firmware` Create firmware bundles from mix
  * `mix firmware.burn` Burn Firmware bundles to SD cards

## 0.2.0

* Enhancements
  * Added support for 0.4.0 system paths