This guide assumes the user knows how to prepare their device for development use. These instructions are device-dependent, but not specific to Mobile NixOS.

Briefly said, the device’s bootloader must be unlocked, meaning that it allows running custom-built operating system images.

Source Code

The project is hosted under the NixOS organization, as mobile-nixos.

Getting the sources

Depending on your configuration, for users with a GitHub account and the proper ssh configuration.

$ git clone git@github.com:NixOS/mobile-nixos.git

Or, for everyone else.

$ git clone https://github.com/NixOS/mobile-nixos.git

Nothing else! Everything required is self-contained.

If you’re interested in testing with a device not-yet-approved, you will have to roll up your sleeves and checkout the relevant branch for the PRs. The GitHub help article may help.

Compiling and Running

This is where it becomes harder to make a simple guide. These are different, heterogeneous, hardware platforms, with different quirks, compilation steps, and mainly, installation steps.

Fear not, look for your particular device on the devices list page, will likely contain the necessary instructions.

Using a known-good revision

Things change, and sometimes things break. This is even more true with Mobile NixOS as the project depends on another moving target, NixOS.

You can look at the latest successful build’s inputs to see which revisions were used for a successful build.

You can then clone Nixpkgs somewhere, checkout that commit ID, and refer to it using NIX_PATH. The following is only an example of how one would do this.

$ cd ~/Projects/
$ git clone https://github.com/NixOS/nixpkgs.git
$ cd nixpkgs
$ git checkout $revision
$ cd ~/Projects/mobile-nixos/
$ export NIX_PATH="nixpkgs=$HOME/Projects/nixpkgs"
$ nix-build [...]

Customizing

You probably will want to toggle options and such things when fiddling with Mobile NixOS, at first. The repository is structured in a way to allow you to add options to an untracked local.nix file. The default nix-build invocations will respect the content of that file as your configuration.

A sample local.nix.

{ lib, ... }:

{
  # Disables splash screens during boot
  mobile.boot.stage-1.splash.enable = false;
}

As Mobile NixOS is a superset on top of NixOS, all NixOS options can be used in this configuration file, though take note that most NixOS options will only affect the stage-2 (rootfs, system.img) build.

The Options list page will be useful, as it provides an overview of all the Mobile NixOS specific options.

Using in your system configuration

As the Mobile NixOS configuration may include fixes and quirks for your device, it is useful to include its configuration into your system’s configuration.nix.

Assuming your NIX_PATH includes mobile-nixos=/path/to/mobile-nixos you can import the Mobile NixOS configuration for your device by doing the following.

# configuration.nix
{
  # "xxx-yyy" is your device "Identifier" from https://mobile.nixos.org/devices,
  # e.g. "google-marlin".
  imports = [
    (import <mobile-nixos/lib/configuration.nix> { device = "xxx-yyy"; })
    # ...
  ];

  # ...
  # Other configurations...
  # ...
}

While it is possible, it is discouraged to directly import the configuration files from the examples directories. They may change in ways breaking your system configuration. It is recommended to copy and edit the configuration files from the examples directories if you are basing your configuration off of an example.

Contributing

This is a big topic, and not something about getting started! Though, quickly noted, contributions are currently handled through GitHub pull requests.

If you are unable or unwilling to use GitHub for pull requests, you can e-mail contributions, following the usual git via e-mail contribution workflow, to my e-mail address, which you will find attached to commits I authored.

Note that there are more in-depth guides about specific contribution topics.