Nerves Burner

December 16, 2025 ยท View on GitHub

CI REUSE status

A user-friendly tool for downloading and writing pre-built Nerves firmware images to MicroSD cards.

Nerves Burner Demo

Supported firmwares

Installation

Install Elixir

Please refer to the Elixir installation docs.

Install fwup (optional)

Nerves Burner uses fwup to unpack and write Nerves firmware images to MicroSD cards. This is convenient but not required. If fwup is not installed, Nerves Burner will provide step-by-step instructions for using alternative tools such as dd (on Linux/macOS) or Etcher (cross-platform) to write the firmware image to your MicroSD card. You do not need to install fwup if you prefer to use these tools. For more information, see the Etcher documentation or refer to your operating system's instructions for using dd.

Installation instructions are at github.com/fwup-home/fwup. If you're using MacOS, just run brew install fwup.

Download Pre-built Executable

Download the latest nerves_burner executable from the Releases page:

curl -L -o nerves_burner https://github.com/fhunleth/nerves_burner/releases/latest/download/nerves_burner
chmod +x nerves_burner

Usage

Run the executable:

./nerves_burner

GitHub hosts the firmware images and sometimes rate limits downloads. If you're affected, let nerves_burner know your personal access token and it will log in for the download:

export GITHUB_TOKEN=your_github_personal_access_token

Create token at: https://github.com/settings/tokens (needs public repo read access only)

Environment Variables

GITHUB_TOKEN / GITHUB_API_TOKEN: Avoid rate limiting

export GITHUB_TOKEN=your_github_personal_access_token

NERVES_BURNER_FORCE_UPDATE: Force update check (for testing)

export NERVES_BURNER_FORCE_UPDATE=1

Firmware Caching

Downloaded firmware is cached in OS-appropriate directories:

  • Linux: ~/.cache/nerves_burner
  • macOS: ~/Library/Caches/nerves_burner
  • Windows: Local app data cache

Troubleshooting

Writing to the MicroSD card times out on macOS

Nerves Burner needs to ask macOS for elevated permissions to write the MicroSD card. Sometimes the dialog box that asks for permission doesn't show up where it's easy to see. It will eventually timeout when permission isn't granted. That's the error message. It seems like trying again always works.

Contributing

Contributions are welcome!

If you maintain Nerves firmware and would like to have it included in nerves_burner, please post an issue or send a PR. We'd like to include maintained community projects as well so that it's easy to discover and try out interesting Nerves projects.