diff --git a/SimPEG/ObjFunction.py b/SimPEG/ObjFunction.py
index 18d9cfc3..cae85ba4 100644
--- a/SimPEG/ObjFunction.py
+++ b/SimPEG/ObjFunction.py
@@ -61,7 +61,7 @@ class BaseObjFunction(object):
         if self.debug: print 'Calling ObjFunction.startup'
 
         if self.reg.mref is None:
-            print 'Regularization has not set mref. SimPEG will set it to m0.'
+            print 'Regularization has not set mref. SimPEG.ObjFunction will set it to m0.'
             self.reg.mref = m0
 
         self.phi_d = np.nan
diff --git a/SimPEG/Parameters.py b/SimPEG/Parameters.py
index 417051df..fa15ff67 100644
--- a/SimPEG/Parameters.py
+++ b/SimPEG/Parameters.py
@@ -56,7 +56,7 @@ class Parameter(object):
         if (self.current is None or
             not self.opt.iter == self.currentIter):
             self.current = self.nextIter()
-            self.currentIter = self.opt.iter
+            self.currentIter = getattr(self.opt, 'iter', 0)
         return self.current
 
     def nextIter(self):
@@ -162,3 +162,16 @@ class BetaSchedule(BetaEstimate):
             self.beta /= self.coolingFactor
 
         return self.beta
+
+
+class UpdateReferenceModel(Parameter):
+
+    mref0 = None
+
+    def nextIter(self):
+        mref = getattr(self, 'm_prev', None)
+        if mref is None:
+            if self.debug: print 'UpdateReferenceModel is using mref0'
+            mref = self.mref0
+        self.m_prev = self.objFunc.m_current
+        return mref