# `mix firmware.burn`
[🔗](https://github.com/nerves-project/nerves/blob/v1.14.1/lib/mix/tasks/firmware.burn.ex#L8)

This task calls `mix firmware` & `mix burn` to burn a new firmware to a SDCard

## 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
    bootloaders and application data partitions. The `upgrade` task only
    modifies the parts of the SDCard required to run the new software.

  * `--verbose` - produce detailed output about release assembly

  * The `mix firmware.burn` task uses the `fwup` tool internally; any extra
    arguments passed to it will be forwarded along to `fwup`. You can read
    about the other supported options in the
    [`fwup` documentation](https://github.com/fwup-home/fwup#invoking).

## Environment variables

  * `NERVES_SYSTEM`    - may be set to a local directory to specify the Nerves
    system image that is used

  * `NERVES_TOOLCHAIN` - may be set to a local directory to specify the
    Nerves toolchain (C/C++ crosscompiler) that is used

## Examples

Upgrade the contents of the SDCard at `/dev/mmcblk0` using the `rpi0` system

```bash
mix firmware.burn --device /dev/mmcblk0 --task upgrade
```

If you are sure there is only one SD card inserted, you can also add the `-y`
flag to skip the confirmation that it is the correct device.

```bash
mix firmware.burn -y
```

---

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