working example for now

nixos/hardware/tongfang.nix

@@ -3,6 +3,12 @@
 # to /etc/nixos/configuration.nix instead.
 { config, lib, pkgs, modulesPath, ... }:
 
+let
+  yt6801 = import ./yt6801.nix {
+    inherit (pkgs) stdenv lib fetchzip;
+    kernel = pkgs.linuxPackages.kernel;
+  };
+in
 {
   imports =
     [ (modulesPath + "/installer/scan/not-detected.nix")
@@ -35,4 +41,4 @@
 
   nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";
   hardware.cpu.amd.updateMicrocode = lib.mkDefault config.hardware.enableRedistributableFirmware;
-}
+}

nixos/hardware/yt6801.nix

@@ -0,0 +1,51 @@
+{
+  kernel,
+  stdenv,
+  lib,
+  fetchzip,
+}:
+
+stdenv.mkDerivation {
+  pname = "yt6801";
+  version = "1.0.29";
+
+  src = fetchzip {
+    url = "https://www.motor-comm.com/Public/Uploads/uploadfile/files/20240812/yt6801-linux-driver-1.0.29.zip";
+    sha256 = "sha256-oz6CeOUN6QWKXxe3WUZljhGDTFArsknjzBuQ4IchGeU=";
+    stripRoot = false;
+  };
+
+  nativeBuildInputs = kernel.moduleBuildDependencies;
+
+  preConfigure = "cd src";
+
+  configurePhase = "true";
+
+  buildFlags = [ "modules" ];
+
+  makeFlags =
+    [
+      "ARCH=${stdenv.hostPlatform.linuxArch}"
+      "KSRC=${kernel.dev}/lib/modules/${kernel.modDirVersion}/build"
+    ]
+    ++ lib.optionals (stdenv.hostPlatform != stdenv.buildPlatform) [
+      "CROSS_COMPILE=${stdenv.cc.targetPrefix}"
+    ];
+
+  installPhase = ''
+    mkdir -p $out/lib/modules/${kernel.modDirVersion}/kernel/drivers/net/ethernet/motorcomm
+    cp src/yt6801.ko $out/lib/modules/${kernel.modDirVersion}/kernel/drivers/net/ethernet/motorcomm/
+  '';
+
+  enableParallelBuilding = true;
+
+  meta = with lib; {
+    description = "Motorcomm yt6801 Network Interface Card driver";
+    homepage = "https://www.motor-comm.com/product/ethernet-control-chip";
+    license = with licenses; [
+      gpl2Plus
+      gpl2Only
+    ];
+    platforms = platforms.linux;
+  };
+}