Bootable NixOS SD image

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Requires an aarch64 host and Nix with flake support.

Use flakes (required)

  mkdir -p ~/.config/nix
  echo 'experimental-features = nix-command flakes' >> ~/.config/nix/nix.conf
  nix-shell -p nixUnstable

Use nix-community binary cache (recommended)

Configure for the current user:

  nix run nixpkgs#cachix -- use nix-community -m user-nixconf -v

Generate a configuration for system-wide installation:

  sudo nix run nixpkgs#cachix -- use nix-community -m nixos -v

Describe

nix flake show "github:nix-community/hardware-mnt-reform"
nix flake list-inputs "github:nix-community/hardware-mnt-reform"

Build

nix build "github:nix-community/hardware-mnt-reform" -L
readlink result

Flash

bzcat ./result/sd-image/nixos-sd-image-*-aarch64-linux.img.bz2 > /dev/mmcblk1

Boot

This image contains a mutable NixOS installation that will initialize itself on the first boot.

Install NixOS on the NVMe

Setup wireless connection

  sudo -i
  wpa_supplicant -B -i wlp1s0 -c <(wpa_passphrase ${SSID} ${PASSWORD})

Use flakes (required)

  mkdir -p ~/.config/nix
  echo 'experimental-features = nix-command flakes' >> ~/.config/nix/nix.conf
  nix-shell -p nixUnstable

Enable binary cache (strongly recommended)

  nix run nixpkgs#cachix -- use nix-community -m user-nixconf -v

Prepare partitions:

• Encrypted (recommended)

    parted /dev/nvme0n1 mklabel gpt
    parted /dev/nvme0n1 mkpart NIX ext4 0% 100%
    cryptsetup luksFormat /dev/nvme0n1p1
    cryptsetup open /dev/nvme0n1p1 nix
    mkfs.ext4 /dev/mapper/nix
    mount /dev/mapper/nix /mnt/
  
    parted /dev/mmcblk0 mklabel gpt
    parted /dev/mmcblk0 mkpart BOOT ext4 0% 100%
    mkfs.ext4 /dev/mmcblk0p1
    mount /dev/mmcblk0p1 /mnt/boot
  

• Plain text

    parted /dev/nvme0n1 mklabel gpt
    parted /dev/nvme0n1 mkpart NIX ext4 0% 100%
    mkfs.ext4 /dev/nvme0n1
    mount /dev/nvme0n1 /mnt
  
    parted /dev/mmcblk0 mklabel gpt
    parted /dev/mmcblk0 mkpart BOOT ext4 0% 100%
    mkfs.ext4 /dev/mmcblk0p1
    mount /dev/mmcblk0p1 /mnt/boot
  

Flash bootloader:

  nix build "github:nix-community/hardware-mnt-reform#ubootReformImx8mq
  echo 0 > /sys/class/block/mmcblk0boot0/force_ro
  dd if=result/flash.bin of=/dev/mmcblk0boot0 bs=1024 seek=33

Generate basic configuration:

nixos-generate-config --root /mnt

Configuration (required)

Add a flake file at /mnt/etc/nixos/flake.nix to import configuration from this repository:

  {
    description = "Configuration for MNT Reform";

    inputs = {
      nixpkgs.url = "github:NixOS/nixpkgs/nixos-22.05";
      reform.url = "github:nix-community/hardware-mnt-reform";
    };

    outputs = { self, nixpkgs, reform }: {

      nixosConfigurations.reform = nixpkgs.lib.nixosSystem {
        system = "aarch64-linux";
        modules = [
          reform.nixosModule
          ./configuration.nix
          ({ pkgs, ... }: {
            nix.package = pkgs.nixFlakes;
            programs.sway.enable = true;
          })
        ];
      };

    };
  }

Start installation:

nixos-install --verbose --impure --flake /mnt/etc/nixos#reform

Shutdown the machine, and flip the DIP switch on the Nitrogen8M_SOM module (under the heatsink). After this step, MNT Reform will boot from NVMe without an SD card. Don't forget to enable binary cache to avoid compiling kernels on the device itself.

For more information see the NixOS manual

How to upgrade

  nixos-rebuild switch --recreate-lock-file --verbose --impure --flake /etc/nixos#reform

  # in case there is new u-boot
  nix build "github:nix-community/hardware-mnt-reform#ubootReformImx8mq"
  echo 0 > /sys/class/block/mmcblk0boot0/force_ro
  dd if=result/flash.bin of=/dev/mmcblk0boot0 bs=1024 seek=33

Important notes

• There may be an issue with the early console with some kernel versions (e.g. I haven't managed to make it work on Linux v5.17.6 at the time of writing this). Just type the password blindly.
• You can choose the NixOS generation at the boot process with UART.

Firmware

Keyboard

Flash the stock keyboard firmware (assuming the keyboard is in programming mode):

doas nix run "github:nix-community/hardware-mnt-reform#reform2-keyboard-fw" -L

Override the keyboard layout:

let
  hardware-mnt-reform =
    builtins.getFlake "github:nix-community/hardware-mnt-reform";
in {
  reform2-keyboard-fw =
    hardware-mnt-reform.packages.aarch64-linux.reform2-keyboard-fw.overrideAttrs
    (_: { patches = [ ./custom-firmware.patch ]; });
}

Motherboard

Build and flash:

nix build  "github:nix-community/hardware-mnt-reform#reform2-lpc-fw-«your-board-rev»" -L
mount «board-rom» /mnt
dd if=result/firmware.bin of="/mnt/firmware.bin" conv=nocreat,notrunc
umount /mnt