diff --git a/flake.nix b/flake.nix
index ae933c5..453b144 100644
--- a/flake.nix
+++ b/flake.nix
@@ -43,7 +43,7 @@
 
           synth = pkgs.runCommandCC "synth" {} ''
             mkdir -p "$out"
-            find ${./src} -name '*.v' -exec ${yosys}/bin/yosys -f ' -sv' -Q -p "synth_ice40 -top topmost -json $out/synth.json -dsp" {} +
+            find ${./src} -name '*.v' -exec ${yosys}/bin/yosys -f ' -sv' -Q -p "synth_ice40 -top topmost -json $out/synth.json" {} +
           '';
 
           pnr-interactive = pkgs.writeScriptBin "pnr-interactive" ''