{
  system = {
    crossSystem = {
      config = "mipsel-unknown-linux-musl";
      gcc = {
        abi = "32";
        arch = "mips32";          # mips32r2?
      };
    };
  };

  description = ''
    Cudy X6
    ********************

    Zyxel NWA50AX is quite close to the GL-MT300N-v2 "Mango" device, but it is based on the MT7621
    chipset instead of the MT7628.

    Installation
    ============

  '';

  module = { pkgs, config, lib, lim, ...}:
    let
      inherit (pkgs.liminix.networking) interface;
      inherit (pkgs.liminix.services) oneshot;
      inherit (pkgs.pseudofile) dir symlink;
      inherit (pkgs) openwrt;

      mac80211 = pkgs.mac80211.override {
        drivers = [ "mt7915e" ];
        klibBuild = config.system.outputs.kernel.modulesupport;
      };
      # v204520220929
      wlan_firmware = pkgs.fetchurl {
        url = "https://github.com/openwrt/mt76/raw/1b88dd07f153b202e57fe29734806744ed006b0e/firmware/mt7915_wa.bin";
        hash = "sha256-wooyefzb0i8640+lwq3vNhcBXRFCtGuo+jiL7afZaKA=";
      };
      wlan_firmware' = pkgs.fetchurl {
        url = "https://github.com/openwrt/mt76/raw/1b88dd07f153b202e57fe29734806744ed006b0e/firmware/mt7915_wm.bin";
        hash = "sha256-k62nQewRuKjBLd5R3RxU4F74YKnQx5zr6gqMMImqVQw=";
      };
      wlan_firmware'' = pkgs.fetchurl {
        url = "https://github.com/openwrt/mt76/raw/1b88dd07f153b202e57fe29734806744ed006b0e/firmware/mt7915_rom_patch.bin";
        hash = "sha256-ifriAjWzFACrxVWCANZpUaEZgB/0pdbhnTVQytx6ddg=";
      };
    in {
      imports = [
        # We include it to ensure the bridge functionality
        # is available on the target kernel.
        ../../modules/bridge
        ../../modules/arch/mipsel.nix
        ../../modules/outputs/tftpboot.nix
        ../../modules/outputs/mtdimage.nix
      ];

      filesystem = dir {
        lib = dir {
          firmware = dir {
            mediatek = dir {
              "mt7915_wa.bin" = symlink wlan_firmware;
              "mt7915_wm.bin" = symlink wlan_firmware';
              "mt7915_rom_patch.bin" = symlink wlan_firmware'';
            };
          };
        };
      };

      hardware = {
        rootDevice = "/dev/mtdblock5";

        defaultOutput = "mtdimage";

        loadAddress = lim.parseInt "0x80001000";
        entryPoint = lim.parseInt "0x80001000";
        # Aligned on 2kb.
        alignment = 2048;

        flash = {
          address = lim.parseInt "0xbc050000";
          eraseBlockSize = 65536;
          size = lim.parseInt "0x1F80000";
        };

        dts = {
          src = "${openwrt.src}/target/linux/ramips/dts/mt7621_cudy_x6-v1.dts";
          includes = [
            "${openwrt.src}/target/linux/ramips/dts"
          ];
        };
        networkInterfaces =
          let
            inherit (config.system.service.network) link;
          in {
            wan = link.build { ifname = "wan"; };
            lan1 = link.build { ifname = "lan1"; };
            lan2 = link.build { ifname = "lan2"; };
            lan3 = link.build { ifname = "lan3"; };
            lan4 = link.build { ifname = "lan4"; };
            wlan0 = link.build {
              ifname = "wlan0";
              dependencies = [ mac80211 ];
            };
            wlan1 = link.build {
              ifname = "wlan1";
              dependencies = [ mac80211 ];
            };
          };
      };

      boot = {
        imageFormat = "fit";
        tftp = {
          # 5MB is nice.
          freeSpaceBytes = 5 * 1024 * 1024;
          loadAddress = lim.parseInt "0x2000000";
        };
      };

      kernel = {
        src = pkgs.fetchurl {
          name = "linux.tar.gz";
          url = "https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.15.137.tar.gz";
          hash = "sha256-PkdzUKZ0IpBiWe/RS70J76JKnBFzRblWcKlaIFNxnHQ=";
        };
        extraPatchPhase = ''
          ${openwrt.applyPatches.ramips}

        '';
        config = {

          RALINK = "y";
          PCI = "y";
          PHY_MT7621_PCI = "y";
          PCIE_MT7621 = "y";
          SOC_MT7621 = "y";
          CLK_MT7621 = "y";
          CLOCKSOURCE_WATCHDOG = "y";

          SERIAL_8250_CONSOLE = "y";
          SERIAL_8250 = "y";
          SERIAL_CORE_CONSOLE = "y";
          SERIAL_OF_PLATFORM = "y";
          SERIAL_8250_NR_UARTS = "3";
          SERIAL_8250_RUNTIME_UARTS = "3";
          SERIAL_MCTRL_GPIO = "y";

          CONSOLE_LOGLEVEL_DEFAULT = "8";
          CONSOLE_LOGLEVEL_QUIET = "4";

          # MTD_UBI_BEB_LIMIT = "20";
          # MTD_UBI_WL_THRESHOLD = "4096";

          MTD = "y";
          MTD_BLOCK = "y";          # fix undefined ref to register_mtd_blktrans_dev
          MTD_RAW_NAND = "y";
          MTD_NAND_MT7621 = "y";
          MTD_NAND_MTK_BMT = "y";      # Bad-block Management Table
          MTD_NAND_ECC_SW_HAMMING= "y";
          MTD_SPI_NAND= "y";
          MTD_OF_PARTS = "y";
          MTD_NAND_CORE= "y";
          MTD_SPLIT_FIRMWARE= "y";
          MTD_SPLIT_FIT_FW= "y";

          PINCTRL = "y";
          PINCTRL_MT7621 = "y";

          I2C = "y";
          I2C_MT7621 = "y";

          SPI = "y";
          MTD_SPI_NOR = "y";
          SPI_MT7621 = "y";
          SPI_MASTER = "y";
          SPI_MEM = "y";

          REGULATOR = "y";
          REGULATOR_FIXED_VOLTAGE = "y";
          RESET_CONTROLLER = "y";
          POWER_RESET = "y";
          POWER_RESET_GPIO = "y";
          POWER_SUPPLY = "y";
          LED_TRIGGER_PHY = "y";

          PCI_DISABLE_COMMON_QUIRKS = "y";
          PCI_DOMAINS = "y";
          PCI_DOMAINS_GENERIC = "y";
          PCI_DRIVERS_GENERIC = "y";
          PCS_MTK_LYNXI = "y";

          SOC_BUS = "y";

          NET = "y";
          ETHERNET = "y";
          WLAN = "y";

          PHYLIB = "y";
          AT803X_PHY = "y";
          FIXED_PHY = "y";
          GENERIC_PHY = "y";
          NET_DSA = "y";
          NET_DSA_MT7530 = "y";
          NET_DSA_MT7530_MDIO = "y";
          NET_DSA_TAG_MTK = "y";
          NET_MEDIATEK_SOC = "y";
          NET_SWITCHDEV = "y";
          NET_VENDOR_MEDIATEK = "y";

          SWPHY = "y";

          GPIOLIB = "y";
          GPIO_MT7621 = "y";
          OF_GPIO = "y";

          EARLY_PRINTK = "y";

          NEW_LEDS = "y";
          LEDS_TRIGGERS = "y";
          LEDS_CLASS = "y";         # required by rt2x00lib
          LEDS_CLASS_MULTICOLOR = "y";
          LEDS_BRIGHTNESS_HW_CHANGED = "y";

          PRINTK_TIME = "y";
        } // lib.optionalAttrs (config.system.service ? vlan) {
          SWCONFIG = "y";
        } // lib.optionalAttrs (config.system.service ? watchdog) {
          RALINK_WDT = "y";  # watchdog
          MT7621_WDT = "y";  # or it might be this one
        };
      };
    };
}