(boot-options)=

# Boot Options

:::{warning}
This function may be highly disruptive.
It may cause major service interruption, so make sure you really
need it and verify your input carefully.
:::

VyOS has several kernel command line options to modify the normal boot
process.
To add an option, select the desired image in GRUB menu at load
time, press **e**, edit the first line, and press **Ctrl-x** to boot when
ready.

```{image} /_static/images/boot-options.webp
:align: center
:width: 80%
```

## Specify custom config file

Tells the system to use specified file instead of `/config/config.boot`.
If specified file does not exist or is not readable, fall back to
default config. No additional verification is performed, so make sure
you specify a valid config file.

```none
vyos-config=/path/to/file
```

To load the *factory default* config, use:

```none
vyos-config=/opt/vyatta/etc/config.boot.default
```

## Disable specific boot process steps

These options disable some boot steps. Make sure you understand the
{ref}`boot process <boot-steps>` well before using them!

```{eval-rst}
.. glossary::

    no-vyos-migrate
      Do not perform config migration.

    no-vyos-firewall
      Do not initialize default firewall chains, renders any firewall
      configuration unusable.
```