# `Nerves.Runtime.FwupOps`
[🔗](https://github.com/nerves-project/nerves_runtime/blob/v0.13.12/lib/nerves_runtime/fwup_ops.ex#L4)

Functions for managing firmware slots via an ops.fw file

The `/usr/share/fwup/ops.fw` is provided by the Nerves system for handling
some eMMC/MicroSD card operations. Look for `fwup-ops.conf` in the Nerves
system source tree for more details. It used to be called
`revert.fw`/`fwup-revert.conf` when it only handled reverting which firmware
image was active.

This is a GenServer to maintain state and serialize firmware slot operations.

# `options`

```elixir
@type options() :: [
  devpath: String.t(),
  fwup_env: %{required(String.t()) => String.t()},
  fwup_extra_options: [String.t()],
  fwup_path: String.t(),
  ops_fw_path: String.t(),
  reboot: boolean()
]
```

Options for calling fwup

* `:devpath` - The location of the storage device (defaults to `"/dev/rootdisk0"`)
* `:fwup_env` - Additional environment variables to pass to `fwup`
* `:fwup_extra_options` - Additional command line options to pass to `fwup` (e.g., `["--unsafe"]`)
* `:fwup_path` - The path to the `fwup` utility
* `:ops_fw_path` - The path to the `ops.fw` file (defaults to `"/usr/share/fwup/ops.fw"`)
* `:reboot` - Call `Nerves.Runtime.reboot/0` after running (defaults to
 `true` on destructive operations)

# `child_spec`

Returns a specification to start this module under a supervisor.

See `Supervisor`.

# `factory_reset`

```elixir
@spec factory_reset(options()) :: :ok | {:error, reason :: any()}
```

Reset the application data partition to its original state

This clears out the application data partition at a low level so that it will
be reformatted on the next boot. If all application settings are stored on
the partition, then this will be like a factory reset. Be aware that many
settings are stored on the application data partition including network
settings like WiFi SSIDs and passwords. Factory reset devices may not connect
to the network afterwards.

# `prevent_revert`

```elixir
@spec prevent_revert(options()) :: :ok | {:error, reason :: any()}
```

Make it impossible to revert to the other partition

This wipes the opposite firmware partition and clears out metadata for it.
Attempts to revert will fail. This is useful if loading a special firmware
temporarily that shouldn't be used again even accidentally.

# `revert`

```elixir
@spec revert(options()) :: :ok | {:error, reason :: any()} | no_return()
```

Revert to the previous firmware

This invokes the "revert" task in the `ops.fw` and then reboots (unless told
otherwise).  The revert task switches the active firmware partition to the
opposite one so that future reboots use the previous firmware.

# `start_link`

```elixir
@spec start_link(options()) :: GenServer.on_start()
```

Start the FwupOps GenServer

Pass in the default options for running `fwup`. They can be overridden
on a one-off basis by passing options to other functions.

# `status`

```elixir
@spec status(options()) ::
  {:ok, %{active: String.t(), next: String.t()}} | {:error, reason :: any()}
```

Return boot status

This invokes the "status" task in the `ops.fw` to report the active
firmware slot and what slot will be tried on the next reboot. The `ops.fw`
is expected to print the slot name or two slot names separated by "->".

# `validate`

```elixir
@spec validate(options()) :: :ok | {:error, reason :: any()}
```

Validate the active partition

For Nerves systems that support automatic rollback of firmware versions, this
marks the partition as good so that it will continue to be used on future
boots.

Call `Nerves.Runtime.validate_firmware/0` instead.

---

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