diff --git a/raptorjit.nix b/raptorjit.nix
index 152a62e089..c6d5c4f897 100644
--- a/raptorjit.nix
+++ b/raptorjit.nix
@@ -9,6 +9,9 @@ mkDerivation rec {
   name = "raptorjit-${version}";
   inherit version;
   src = source;
+  preBuild = ''
+    make bootstrapclean
+  '';
   buildInputs = [ luajit ];  # LuaJIT to bootstrap DynASM
   installPhase = ''
     mkdir -p $out/bin