diff --git a/services/univention-s4-connector/modules/univention/s4connector/s4/__init__.py b/services/univention-s4-connector/modules/univention/s4connector/s4/__init__.py
index 83db5dd..9084615 100644
--- a/services/univention-s4-connector/modules/univention/s4connector/s4/__init__.py
+++ b/services/univention-s4-connector/modules/univention/s4connector/s4/__init__.py
@@ -353,12 +353,14 @@ def samaccountname_dn_mapping(s4connector, given_object, dn_mapping_stored, ucso
 						newdn = unicode(result[0][0], 'utf8')
 					else:
 						s4_rdn = ldap.dn.str2dn(result[0][0])[0]
-						new_s4_dn = unicode(ldap.dn.dn2str([s4_rdn] + exploded_dn[1:]), 'utf8')
-						pos = new_s4_dn.lower().rfind(s4connector.lo_s4.base.lower())
-						newdn = new_s4_dn[:pos] + s4connector.lo.base
+						tmp_dn_string = unicode(ldap.dn.dn2str([s4_rdn] + exploded_dn[1:]), 'utf8')
+						pos = tmp_dn_string.lower().rfind(s4connector.lo.base.lower())
+						newdn = tmp_dn_string[:pos] + s4connector.lo_s4.base
 				else:
 					newdn_rdn = [('cn', fst_rdn_value_utf8, ldap.AVA_STRING)]
-					newdn = unicode(ldap.dn.dn2str([newdn_rdn] + exploded_dn[1:]), 'utf8')  # new object, don't need to change
+					tmp_dn_string = unicode(ldap.dn.dn2str([newdn_rdn] + exploded_dn[1:]), 'utf8')  # new object, don't need to change
+					pos = tmp_dn_string.lower().rfind(s4connector.lo.base.lower())
+					newdn = tmp_dn_string[:pos] + s4connector.lo_s4.base
 				ud.debug(ud.LDAP, ud.INFO, "samaccount_dn_mapping: newdn: %s" % newdn)
 			else:
 				# get the object to read the sAMAccountName in S4 and use it as name
@@ -2453,8 +2455,7 @@ class s4(univention.s4connector.ucs):
 				old_dn = tmp_object['dn']
 			if hasattr(self.property[property_type], 'position_mapping'):
 				for mapping in self.property[property_type].position_mapping:
-					old_dn = self._subtree_replace(old_dn.lower(), mapping[1].lower(), mapping[0].lower())
-				old_dn = self._subtree_replace(old_dn, self.lo.base, self.lo_s4.base)
+					old_dn = self._subtree_replace(old_dn.lower(), mapping[0].lower(), mapping[1].lower())
 			# the old object was moved in UCS, but does this object exist in S4?
 			try:
 				old_object = self.lo_s4.lo.search_ext_s(compatible_modstring(old_dn), ldap.SCOPE_BASE, 'objectClass=*', timeout=-1, sizelimit=0)
diff --git a/test/ucs-ec2-tools b/test/ucs-ec2-tools
index 755b752..bc0b7f6 160000
--- a/test/ucs-ec2-tools
+++ b/test/ucs-ec2-tools
@@ -1 +1 @@
-Subproject commit 755b752d461b62ba29666294762e04f00ea9a74f
+Subproject commit bc0b7f6b1dfba8ec6dddbe50fa217fafe14ce4c8