diff --git a/extensions/openpower-pels/pce_identity.cpp b/extensions/openpower-pels/pce_identity.cpp
index 43c5b21..6a6f257 100644
--- a/extensions/openpower-pels/pce_identity.cpp
+++ b/extensions/openpower-pels/pce_identity.cpp
@@ -38,7 +38,7 @@
     pel >> _pceName;
 }
 
-void PCEIdentity::flatten(Stream& pel)
+void PCEIdentity::flatten(Stream& pel) const
 {
     pel << _type << _size << _flags << _mtms << _pceName;
 }