diff --git a/src/sim/serialize.hh b/src/sim/serialize.hh
--- a/src/sim/serialize.hh
+++ b/src/sim/serialize.hh
@@ -99,13 +99,15 @@
 }
 
 template <class T>
-bool optParamIn(CheckpointIn &cp, const std::string &name, T &param);
+bool optParamIn(CheckpointIn &cp, const std::string &name, T &param,
+                bool warn = true);
 
 template <typename DataType, typename BitUnion>
 bool optParamIn(CheckpointIn &cp, const std::string &name,
-                BitfieldBackend::BitUnionOperators<DataType, BitUnion> &p)
+                BitfieldBackend::BitUnionOperators<DataType, BitUnion> &p,
+                bool warn = true)
 {
-    return optParamIn(cp, name, p.__data);
+    return optParamIn(cp, name, p.__data, warn);
 }
 
 template <class T>
# Node ID 08141b27e53287f4a9fc30b8b3a8dc60d984f869
# Parent  5723d29b779f6141bc2dd95dec8207ee09bdaa7c
diff --git a/src/sim/serialize.cc b/src/sim/serialize.cc
--- a/src/sim/serialize.cc
+++ b/src/sim/serialize.cc
@@ -222,12 +222,13 @@
 
 template <class T>
 bool
-optParamIn(CheckpointIn &cp, const string &name, T &param)
+optParamIn(CheckpointIn &cp, const string &name, T &param, bool warn)
 {
     const string &section(Serializable::currentSection());
     string str;
     if (!cp.find(section, name, str) || !parseParam(str, param)) {
-        warn("optional parameter %s:%s not present\n", section, name);
+        if (warn)
+            warn("optional parameter %s:%s not present\n", section, name);
         return false;
     } else {
         return true;
@@ -383,7 +384,8 @@
     template void                                                       \
     paramIn(CheckpointIn &cp, const string &name, type & param);        \
     template bool                                                       \
-    optParamIn(CheckpointIn &cp, const string &name, type & param);     \
+    optParamIn(CheckpointIn &cp, const string &name, type & param,      \
+               bool warn);                                              \
     template void                                                       \
     arrayParamOut(CheckpointOut &os, const string &name,                \
                   type const *param, unsigned size);                    \