First attempt at cross compiling sd image

.gitignore

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+.direnv/
+target
+result

flake.lock

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+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1701693815,
+        "narHash": "sha256-7BkrXykVWfkn6+c1EhFA3ko4MLi3gVG0p9G96PNnKTM=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "09ec6a0881e1a36c29d67497693a67a16f4da573",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs",
+        "utils": "utils"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    },
+    "utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1701680307,
+        "narHash": "sha256-kAuep2h5ajznlPMD9rnQyffWG8EM/C73lejGofXvdM8=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "4022d587cbbfd70fe950c1e2083a02621806a725",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

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+{
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
+    utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, utils }:
+    let supportedSystems = [ "x86_64-linux" "aarch64-linux" ];
+    in (utils.lib.eachSystem supportedSystems (system:
+      let pkgs = import nixpkgs { inherit system; };
+      in {
+        formatter = pkgs.nixfmt;
+        packages.pi4-sdimage = (self.nixosConfigurations.pi4.extendModules {
+          modules = [{
+            config.nixpkgs = {
+              hostPlatform.system = "aarch64-linux";
+              buildPlatform.system = system;
+            };
+          }];
+        }).config.system.build.sdImage;
+      })) // {
+        nixosModules.minify = { ... }: {
+          disabledModules = [ "profiles/base.nix" ];
+          config = {
+            nix.enable = false;
+            programs.nano.enable = true;
+          };
+        };
+
+        nixosConfigurations.pi4 = nixpkgs.lib.nixosSystem {
+          system = "aarch64-linux";
+          modules = [
+            self.nixosModules.minify
+            "${nixpkgs}/nixos/modules/installer/sd-card/sd-image-aarch64.nix"
+          ];
+        };
+      };
+}