# `mix burn`
[🔗](https://github.com/nerves-project/nerves/blob/v1.14.1/lib/mix/tasks/burn.ex#L10)

Writes the generated firmware image to an attached SDCard or file.

By default, this task detects attached SDCards and then invokes `fwup`
to overwrite the contents of the selected SDCard with the new image.
Data on the SDCard will be lost, so be careful.

## Command line options

  * `--device <filename>` - skip SDCard detection and write the image to
    the specified filename. SDCard paths depend on the operating system, but
    have a form like `/dev/sdc` or `/dev/mmcblk0`. You may also specify a
    filename to create an image that can be used with a bulk memory programmer
    or copied to an SDCard manually with a utility like `dd`.

  * `--task <name>` - apply the specified `fwup` task. See the `fwup.conf`
    file that was used to create the firmware image for options. By
    convention, the `complete` task writes everything to the SDCard including
    bootloader and application data partitions. The `upgrade` task only
    modifies the parts of the SDCard required to run the new software.

  * `--firmware <name>` - (Optional) The path to the fw file to use.
    Defaults to `<image_path>/<otp_app>.fw`

## Examples

```
# Upgrade the contents of the SDCard located at /dev/mmcblk0
mix burn --device /dev/mmcblk0 --task upgrade
```

# `firmware_file`

```elixir
@spec firmware_file(keyword()) :: String.t()
```

---

*Consult [api-reference.md](api-reference.md) for complete listing*