diff --git a/npc/flake.nix b/npc/flake.nix
index b2fd2fa..32aa36a 100644
--- a/npc/flake.nix
+++ b/npc/flake.nix
@@ -37,6 +37,7 @@
             sbt
             nur.xin.nvboard
             self.packages.${system}.circt
+            yosys
           ];
           buildInputs = [
             verilator