diff --git a/mrblib/hash.rb b/mrblib/hash.rb
index 3c08ccd9c..d24fce849 100644
--- a/mrblib/hash.rb
+++ b/mrblib/hash.rb
@@ -197,7 +197,7 @@ class Hash
   end
 
   def __update(h)
-    h.each_key{|k| self[k] = h[v]}
+    h.each_key{|k| self[k] = h[k]}
     self
   end
 end