diff --git a/emsdk_manifest.json b/emsdk_manifest.json
index 376415a..f1d69e1 100644
--- a/emsdk_manifest.json
+++ b/emsdk_manifest.json
@@ -183,7 +183,7 @@
     "zipfile_prefix": "%releases-tag%-",
     "install_path": "fastcomp",
     "activated_path": "%installation_dir%/emscripten",
-    "activated_cfg": "LLVM_ROOT='%installation_dir%/fastcomp/bin';BINARYEN_ROOT='%installation_dir%'",
+    "activated_cfg": "LLVM_ROOT='%installation_dir%/fastcomp/bin';BINARYEN_ROOT='%installation_dir%';EMSCRIPTEN_NATIVE_OPTIMIZER='%installation_dir%/bin/optimizer%.exe%'",
     "emscripten_releases_hash": "%releases-tag%",
     "pregenerated_cache": "asmjs"
   },