start working on making flake work

flake.lock

@@ -1,5 +1,22 @@
 {
   "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1726560853,
+        "narHash": "sha256-X6rJYSESBVr3hBoH0WbKE5KvhPU5bloyZ2L4K60/fPQ=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "c1dfcf08411b08f6b8615f7d8971a2bfa81d5e8a",
+        "type": "github"
+      },
+      "original": {
+        "id": "flake-utils",
+        "type": "indirect"
+      }
+    },
     "nixpkgs": {
       "locked": {
         "lastModified": 1723637854,
@@ -18,8 +35,24 @@
     },
     "root": {
       "inputs": {
+        "flake-utils": "flake-utils",
         "nixpkgs": "nixpkgs"
       }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
     }
   },
   "root": "root",

flake.nix

@@ -5,17 +5,9 @@
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
   };
 
-  outputs = inputs@{ nixpkgs, ... }:
+  outputs = inputs@{ nixpkgs, flake-utils, ... }:
     let
-      # litex-overlay = final: prev: {
-      #   pythonPackagesExtensions = prev.pythonPackagesExtensions ++ [
-      #     (python-final: python-prev: {
-      #       litex = python-final.callPackage (import ./litex.nix) { };
-      #       # can add more packages here!
-      #     })
-      #   ];
-      # };
-      litex-overlay = import ./litex;
+		python-overlay = import ./python.nix;
       systems = [ "x86_64-linux" "aarch64-linux" "aarch64-darwin" "x86_64-darwin" ];
       forAllSystems = function:
         nixpkgs.lib.genAttrs systems (system: function (
@@ -23,38 +15,31 @@
             inherit system;
             config.allowUnfree = true;
             overlays = [
-            ]; # patches, version pins, new pkgs here.
+				python-overlay
+            ]; 
           }
         ));
     in {
       packages = forAllSystems (pkgs: {
         sim = import ./sim/package.nix pkgs;
+
       });
       devShells = forAllSystems (pkgs: {
         default = pkgs.mkShell {
           packages = with pkgs; [
             (python3.withPackages (ps: with ps; [ 
-              cocotb
               amaranth
             ]))
             yosys
             nextpnr
-            pkgsCross.riscv64.buildPackages.gcc
-            gnumake
-            wishbone-tool
             # simulators
-            verilog
+            iverilog
             verilator
             # support package
             trellis
             # loader
             openfpgaloader
             ecpdap # easier to poke probes.
-
-            # for building the simulator
-            cmake
-            ninja
-            mdbook
           ];
         };
       });

python.nix

@@ -0,0 +1,18 @@
+# overlay python patched version with amaranth/boards updated.
+final: prev: {
+	python3 = prev.python3.override {
+		packageOverrides = pyfinal: pyprev: {
+		amaranth = pyprev.amaranth.overridePythonAttrs {
+			version = "0.6.0.dev53";
+			src = prev.pkgs.fetchFromGitHub {
+				owner = "amaranth-lang";
+				repo = "amaranth";
+				rev = "e30d822a7d93ee615e70e95a9958051dcc794802";
+				hash = "sha256-A46CMWGvqUFTp3geFFccUM9M7iECmNndzWm2GxA8XbE";
+			};
+			doCheck = false;
+			# installCheckPhase = "${prev.python3.interpreter} -m unittest discover -t . -s tests -v";
+		};
+		};
+	};
+}