configuration.nix/hosts/rico2/hardware/filesystem.nix

{...}: {
  fileSystems."/" = {
    device = "/dev/disk/by-partlabel/NIXOS_ROOT";
    fsType = "btrfs";
    options = ["noatime" "compress=zstd"];
  };
  fileSystems."/boot" = {
    device = "/dev/disk/by-partlabel/ESP";
    fsType = "vfat";
  };
}