NixOS on ARM/Initial Configuration

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NixOS installation & configuration

This article or section is out of date.

Reason: The kernel version recommendations of this section are severely outdated. This section should be rewritten to be generic and refer people to the board-specific page. Only the board specific page should make recommendations about the kernel. (Discuss in Talk:NixOS on ARM/Initial Configuration)
Once the page has been updated this notice can be removed.

The installation image is actually a MBR partition table plus two partitions; a FAT16 /boot and a ext4 root filesystem. The image is designed such that it's possible to directly reuse the SD image's partition layout and "install" NixOS on the very same SD card by simply replacing the default configuration.nix and running nixos-rebuild. Using this installation method is strongly recommended, though if you know exactly what you're doing and how U-Boot on your board works, you can use nixos-install as usual. To help with the SD card installation method, the boot scripts on the image automatically resize the rootfs partition to fit the SD card on the first boot.

• To generate a default /etc/nixos/configuration.nix file, run sudo nixos-generate-config.

• You can also use an existing template:

/etc/nixos/configuration.nix

{ config, pkgs, lib, ... }:
{
  # NixOS wants to enable GRUB by default
  boot.loader.grub.enable = false;
  # Enables the generation of /boot/extlinux/extlinux.conf
  boot.loader.generic-extlinux-compatible.enable = true;
 
  # !!! If your board is a Raspberry Pi 1, select this:
  boot.kernelPackages = pkgs.linuxPackages_rpi;
  # On other boards, pick a different kernel, note that on most boards with good mainline support, default, latest and hardened should all work
  # Others might need a BSP kernel, which should be noted in their respective wiki entries
  
  # nixos-generate-config should normally set up file systems correctly
  imports = [ ./hardware-configuration.nix ];
  # If not, you can set them up manually as shown below
  /*
  fileSystems = {
    # Prior to 19.09, the boot partition was hosted on the smaller first partition
    # Starting with 19.09, the /boot folder is on the main bigger partition.
    # The following is to be used only with older images. Note such old images should not be considered supported anymore whatsoever, but if you installed back then, this might be needed
    /*
    "/boot" = {
      device = "/dev/disk/by-label/NIXOS_BOOT";
      fsType = "vfat";
    };
    */
    "/" = {
      device = "/dev/disk/by-label/NIXOS_SD";
      fsType = "ext4";
    };
  };
  */
    
  # !!! Adding a swap file is optional, but recommended if you use RAM-intensive applications that might OOM otherwise. 
  # Size is in MiB, set to whatever you want (though note a larger value will use more disk space).
  # swapDevices = [ { device = "/swapfile"; size = 1024; } ];
}

Note: the default configuration.nix will contain something like imports = [ <nixos/modules/installer/sd-card/sd-image-armv7l-multiplatform.nix> ]; do not include that in your final installation or you will experience interesting problems. It is only for building the installation image!

First rebuild on ARMv6 and ARMv7

To rebuild your system, run: sudo nixos-rebuild switch

Note: Instructions removed since they referred to a long abandoned user-provided cache...