diff --git a/flake.nix b/flake.nix
index 1f52d38..8cb8a25 100644
--- a/flake.nix
+++ b/flake.nix
@@ -7,13 +7,24 @@
 
   outputs = inputs@{ nixpkgs, ... }:
     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;
       systems = [ "x86_64-linux" "aarch64-linux" "aarch64-darwin" "x86_64-darwin" ];
       forAllSystems = function:
         nixpkgs.lib.genAttrs systems (system: function (
           import nixpkgs {
             inherit system;
             config.allowUnfree = true;
-            overlays = []; # patches, version pins here.
+            overlays = [
+              litex-overlay
+            ]; # patches, version pins, new pkgs here.
           }
         ));
 
@@ -21,9 +32,12 @@
       devShells = forAllSystems (pkgs: {
         default = pkgs.mkShell {
           packages = with pkgs; [
-            python3
-            python3Packages.cocotb
-            python3Packages.cocotb-bus
+            (python3.withPackages (ps: with ps; [ 
+              cocotb
+              cocotb-bus
+              litex
+              amaranth
+            ]))
             yosys
             nextpnr
             # simulators
@@ -33,6 +47,7 @@
             trellis
             # loader
             openfpgaloader
+            ecpdap # easier to poke probes.
           ];
         };
 
diff --git a/litex/default.nix b/litex/default.nix
new file mode 100644
index 0000000..34ae2fd
--- /dev/null
+++ b/litex/default.nix
@@ -0,0 +1,11 @@
+# an overlay to 
+let 
+  tag = "2023.12";
+in final: prev: {
+  pythonPackagesExtensions = prev.pythonPackagesExtensions ++ [
+    (python-final: python-prev: {
+      litex = python-final.callPackage(import ./litex.nix tag) { };
+    })
+  ];
+}
+
diff --git a/litex/litex.nix b/litex/litex.nix
new file mode 100644
index 0000000..5619107
--- /dev/null
+++ b/litex/litex.nix
@@ -0,0 +1,36 @@
+tag: {
+  pkgs 
+, lib
+, buildPythonPackage 
+, pyserial
+, migen
+, requests
+, colorama
+, packaging
+, setuptools
+}: buildPythonPackage {
+  pname = "litex";
+  version = "${tag}";
+  pyproject = true;
+
+  src = pkgs.fetchFromGitHub {
+    owner = "enjoy-digital";
+    repo = "litex";
+    rev = "${tag}";
+    hash = "sha256-OcwqYLQ7ec2vTewdIJqP/aTCJ4yI43OIOkTMD/hIKO0=";
+  };
+
+  buildInputs = [
+    setuptools
+  ];
+
+  propagatedBuildInputs = [
+    migen
+    requests
+    pyserial
+    colorama
+    packaging
+  ];
+
+  doCheck = false;
+}