{
  disko.devices = {
    disk = {
      main = {
        type = "disk";
        device = "/dev/sda";
        content = {
          type = "gpt";
          partitions = {
            MBR = {
              size = "1M";
              type = "EF02"; # for grub MBR, no UEFI on this system.
            };
            luks = {
              # Partial NixOS for my side.
              size = "300G";
              content = {
                type = "luks";
                name = "crypted";
                # disable settings.keyFile if you want to use interactive password entry
                #passwordFile = "/tmp/secret.key"; # Interactive
                settings = {
                  allowDiscards = true;
                  extraFormatArgs = [ "--type luks1" ];
                  # keyFile = "/tmp/secret.key";
                };
                # additionalKeyFiles = [ "/tmp/additionalSecret.key" ];
                content = {
                  type = "btrfs";
                  extraArgs = [ "-f" ];
                  subvolumes = {
                    "/root" = {
                      mountpoint = "/";
                      mountOptions = [
                        "compress=zstd"
                        "noatime"
                      ];
                    };
                    "/home" = {
                      mountpoint = "/home";
                      mountOptions = [
                        "compress=zstd"
                        "noatime"
                      ];
                    };
                    "/nix" = {
                      mountpoint = "/nix";
                      mountOptions = [
                        "compress=zstd"
                        "noatime"
                      ];
                    };
                  };
                };
              };
            };
	    encryptedSwap = {
		size = "16G";
		content = {
			type = "swap";
			randomEncryption = true;
			priority = 100;
		};
	    };
          };
        };
      };
    };
  };
}

# Edit this configuration file to define what should be installed on
# your system. Help is available in the configuration.nix(5) man page, on
# https://search.nixos.org/options and in the NixOS manual (`nixos-help`).

{ config, lib, pkgs, ... }:

{
  imports =
    [ # Include the results of the hardware scan.
      ./hardware-configuration.nix
      "${builtins.fetchTarball "https://github.com/nix-community/disko/archive/master.tar.gz"}/module.nix"
      ./disk-config.nix
    ];

  # Use the GRUB 2 boot loader.
  boot.loader.grub.enable = true;
  boot.loader.grub.efiSupport = false;
  # boot.loader.grub.efiInstallAsRemovable = true;
  # boot.loader.efi.efiSysMountPoint = "/boot/efi";
  # Define on which hard drive you want to install Grub.
  # boot.loader.grub.device = "/dev/sda"; # or "nodev" for efi only

  boot.loader.grub.enableCryptodisk = true;
  boot.initrd.luks.devices.cryptroot.device = "/dev/sda";

  # networking.hostName = "nixos"; # Define your hostname.
  # Pick only one of the below networking options.
  # networking.wireless.enable = true;  # Enables wireless support via wpa_supplicant.
  # networking.networkmanager.enable = true;  # Easiest to use and most distros use this by default.

  # Set your time zone.
  # time.timeZone = "Europe/Amsterdam";

  # Configure network proxy if necessary
  # networking.proxy.default = "http://user:password@proxy:port/";
  # networking.proxy.noProxy = "127.0.0.1,localhost,internal.domain";

  # Select internationalisation properties.
  # i18n.defaultLocale = "en_US.UTF-8";
  # console = {
  #   font = "Lat2-Terminus16";
  #   keyMap = "us";
  #   useXkbConfig = true; # use xkb.options in tty.
  # };

  # Enable the X11 windowing system.
  # services.xserver.enable = true;


  

  # Configure keymap in X11
  # services.xserver.xkb.layout = "us";
  # services.xserver.xkb.options = "eurosign:e,caps:escape";

  # Enable CUPS to print documents.
  # services.printing.enable = true;

  # Enable sound.
  # services.pulseaudio.enable = true;
  # OR
  # services.pipewire = {
  #   enable = true;
  #   pulse.enable = true;
  # };

  # Enable touchpad support (enabled default in most desktopManager).
  # services.libinput.enable = true;

  # Define a user account. Don't forget to set a password with ‘passwd’.
  # users.users.alice = {
  #   isNormalUser = true;
  #   extraGroups = [ "wheel" ]; # Enable ‘sudo’ for the user.
  #   packages = with pkgs; [
  #     tree
  #   ];
  # };

  # programs.firefox.enable = true;

  # List packages installed in system profile.
  # You can use https://search.nixos.org/ to find more packages (and options).
  # environment.systemPackages = with pkgs; [
  #   vim # Do not forget to add an editor to edit configuration.nix! The Nano editor is also installed by default.
  #   wget
  # ];

  # Some programs need SUID wrappers, can be configured further or are
  # started in user sessions.
  # programs.mtr.enable = true;
  # programs.gnupg.agent = {
  #   enable = true;
  #   enableSSHSupport = true;
  # };

  # List services that you want to enable:

  # Enable the OpenSSH daemon.
  # services.openssh.enable = true;

  # Open ports in the firewall.
  # networking.firewall.allowedTCPPorts = [ ... ];
  # networking.firewall.allowedUDPPorts = [ ... ];
  # Or disable the firewall altogether.
  # networking.firewall.enable = false;

  # Copy the NixOS configuration file and link it from the resulting system
  # (/run/current-system/configuration.nix). This is useful in case you
  # accidentally delete configuration.nix.
  # system.copySystemConfiguration = true;

  # This option defines the first version of NixOS you have installed on this particular machine,
  # and is used to maintain compatibility with application data (e.g. databases) created on older NixOS versions.
  #
  # Most users should NEVER change this value after the initial install, for any reason,
  # even if you've upgraded your system to a new NixOS release.
  #
  # This value does NOT affect the Nixpkgs version your packages and OS are pulled from,
  # so changing it will NOT upgrade your system - see https://nixos.org/manual/nixos/stable/#sec-upgrading for how
  # to actually do that.
  #
  # This value being lower than the current NixOS release does NOT mean your system is
  # out of date, out of support, or vulnerable.
  #
  # Do NOT change this value unless you have manually inspected all the changes it would make to your configuration,
  # and migrated your data accordingly.
  #
  # For more information, see `man configuration.nix` or https://nixos.org/manual/nixos/stable/options#opt-system.stateVersion .
  system.stateVersion = "25.05"; # Did you read the comment?

}

https://github.com/nix-community/disko/blob/d74db625a5cf3f46cf8fa545d6ef10bd3463ea07/lib/types/gpt.nix#L259

if ! blkid "${config.device}" >&2; then
  sgdisk --clear "${config.device}"
fi

I can't tell if I found a bug or if I'm just not understanding this; blkid exits with code 2 when run on a blank (all 00) block device, in which case it... clears the gpt label? that isn't there?

In reply to @pink_rocky:tchncs.de
Okay, right now I’ve gotten it to error on the build with:
"Unable to read fragment cache entry"
"Unable to read page"
"unknown filesystem type 'btrfs'"

In reply to @pink_rocky:tchncs.de
configuration.nix