enable rpi4 hardware

flake.lock

@@ -1,5 +1,20 @@
 {
   "nodes": {
+    "nixos-hardware": {
+      "locked": {
+        "lastModified": 1640686209,
+        "narHash": "sha256-6glXUlKRDhEhNuYx6r3fXU6KH2/Vq9mJZjB9oUpwrmc=",
+        "owner": "NixOS",
+        "repo": "nixos-hardware",
+        "rev": "46df95ca81e7e4cf3458cdb4b7d1714b5fce9da5",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "repo": "nixos-hardware",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
         "lastModified": 1640798027,
@@ -17,6 +32,7 @@
     },
     "root": {
       "inputs": {
+        "nixos-hardware": "nixos-hardware",
         "nixpkgs": "nixpkgs"
       }
     }

flake.nix

@@ -1,12 +1,16 @@
 {
   inputs.nixpkgs.url = "nixpkgs/nixos-21.11";
+  inputs.nixos-hardware.url = "github:NixOS/nixos-hardware";
 
-  outputs = { self, nixpkgs, ... }:
+  outputs = { self, nixpkgs, nixos-hardware, ... }:
     let
 
       mypkgs = import ./pkgs;
       deploy = import lib/deploy.nix;
-      hardware = import lib/hardware.nix "${nixpkgs}/nixos/modules";
+
+      hardware =
+        nixos-hardware.nixosModules //
+        import lib/hardware.nix "${nixpkgs}/nixos/modules";
 
       forAllSystems = f: builtins.listToAttrs (map
         (name: { inherit name; value = f name; })

lib/deploy.nix

@@ -95,6 +95,7 @@ in
     { meta.nixpkgs = nixpkgs.legacyPackages.${system}; } //
     builtins.mapAttrs
       (name: value: {
+        nixpkgs.system = value.config.nixpkgs.system; # needed for multi-arch deployments
         imports = value.extraArgs.modules ++ [
           ({ config, ... }: { inherit (config.sconfig) deployment; })
         ];

modules/profiles/desktop.nix

@@ -106,6 +106,8 @@ with lib;
 
     boot.kernelPackages = pkgs.linuxPackages_5_15;
 
+    boot.binfmt.emulatedSystems = [ "aarch64-linux" ];
+
     boot.loader.timeout =
       if config.boot.loader.systemd-boot.enable
       then null else lib.mkOverride 9999 99;