diff --git a/src/coqutil/Map/Interface.v b/src/coqutil/Map/Interface.v
index 4440dfb2..97537680 100644
--- a/src/coqutil/Map/Interface.v
+++ b/src/coqutil/Map/Interface.v
@@ -1,3 +1,4 @@
+Set Universe Polymorphism.
 Require Import coqutil.sanity.
 Require Import coqutil.Datatypes.HList.
 Require Import coqutil.Datatypes.List.
diff --git a/src/coqutil/Word/Interface.v b/src/coqutil/Word/Interface.v
index 13ecbf5f..4b0cbbc8 100644
--- a/src/coqutil/Word/Interface.v
+++ b/src/coqutil/Word/Interface.v
@@ -1,3 +1,4 @@
+Set Universe Polymorphism.
 (* Specification of two's complement machine words wrt Z *)
 
 Require Import Coq.ZArith.BinIntDef Coq.ZArith.BinInt.