{ ... }:
{
  # Vultr's first virtio disk is normally /dev/vda. Change this before
  # deployment if the selected image exposes its system disk differently.
  disko.devices.disk.main = {
    type = "disk";
    device = "/dev/vda";
    content = {
      type = "gpt";
      partitions = {
        bios = {
          size = "1M";
          type = "EF02";
        };

        ESP = {
          size = "512M";
          type = "EF00";
          content = {
            type = "filesystem";
            format = "vfat";
            mountpoint = "/boot";
            mountOptions = [
              "fmask=0077"
              "dmask=0077"
            ];
          };
        };

        swap = {
          size = "8G";
          content = {
            type = "swap";
          };
        };

        root = {
          size = "100%";
          content = {
            type = "filesystem";
            format = "ext4";
            mountpoint = "/";
          };
        };
      };
    };
  };

  # Install GRUB for both legacy BIOS and EFI-capable Vultr plans.
  boot.loader = {
    grub = {
      enable = true;
      devices = [ "/dev/vda" ];
      efiSupport = true;
      efiInstallAsRemovable = true;
    };
    efi.canTouchEfiVariables = false;
  };
}