diff --git a/iCubErzelli02/hardware/mechanicals/right_arm-eb28-j8_11-mec.xml b/iCubErzelli02/hardware/mechanicals/right_arm-eb28-j8_11-mec.xml
index 864b42fdf0..7b75cbac90 100644
--- a/iCubErzelli02/hardware/mechanicals/right_arm-eb28-j8_11-mec.xml
+++ b/iCubErzelli02/hardware/mechanicals/right_arm-eb28-j8_11-mec.xml
@@ -31,14 +31,14 @@
                             
         <param name ="matrixJ2M"> 
             1.000   0.000   0.000   0.000
-            1.000  +1.000   0.000   0.000
+           -1.000  +1.000   0.000   0.000
             0.000   0.000   1.000   0.000
             0.000   0.000   0.000   1.000   
         </param>
 
          <param name ="matrixM2J"> 
             1.000   0.000   0.000   0.000
-           -1.000  +1.000   0.000   0.000
+            1.000  +1.000   0.000   0.000
             0.000   0.000   1.000   0.000
             0.000   0.000   0.000   1.000   
         </param>