diff --git a/hmm.json b/hmm.json
index 984f54166..18062d231 100644
--- a/hmm.json
+++ b/hmm.json
@@ -62,7 +62,7 @@
       "name": "polymod",
       "type": "git",
       "dir": null,
-      "ref": "c858b48",
+      "ref": "cd4600c",
       "url": "https://github.com/larsiusprime/polymod"
     },
     {