diff --git a/npc/flake.lock b/npc/flake.lock
index f32f7c0..76de6c7 100644
--- a/npc/flake.lock
+++ b/npc/flake.lock
@@ -34,6 +34,22 @@
         "type": "github"
       }
     },
+    "nixpkgs-circt162": {
+      "locked": {
+        "lastModified": 1705645507,
+        "narHash": "sha256-tX3vipIAmNDBA8WNWG4oY4KyTfnm2YieTHO2BhG8ISA=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "7995cae3ad60e3d6931283d650d7f43d31aaa5c7",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "7995cae3ad60e3d6931283d650d7f43d31aaa5c7",
+        "type": "github"
+      }
+    },
     "nur-xin": {
       "inputs": {
         "nixpkgs": [
@@ -58,6 +74,7 @@
       "inputs": {
         "flake-utils": "flake-utils",
         "nixpkgs": "nixpkgs",
+        "nixpkgs-circt162": "nixpkgs-circt162",
         "nur-xin": "nur-xin"
       }
     },
diff --git a/npc/flake.nix b/npc/flake.nix
index b101382..564efa0 100644
--- a/npc/flake.nix
+++ b/npc/flake.nix
@@ -1,6 +1,7 @@
 {
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    nixpkgs-circt162.url = "github:NixOS/nixpkgs/7995cae3ad60e3d6931283d650d7f43d31aaa5c7";
     flake-utils.url = "github:numtide/flake-utils";
     nur-xin = {
       url = "git+https://git.xinyang.life/xin/nur.git";
@@ -38,7 +39,7 @@
             cmake
             sbt
             nur.xin.nvboard
-            self.packages.${system}.circt
+            nixpkgs-circt162.legacyPackages.${system}.circt
             yosys
           ];
           buildInputs = [