diff --git a/data/etc/revpipyload/revpipyload.conf b/data/etc/revpipyload/revpipyload.conf
index 3f346fe..603af70 100644
--- a/data/etc/revpipyload/revpipyload.conf
+++ b/data/etc/revpipyload/revpipyload.conf
@@ -3,6 +3,7 @@ autoreload = 1
 autoreloaddelay = 5
 autostart = 1
 plcworkdir = /var/lib/revpipyload
+plcworkdir_set_uid = 0
 plcprogram = program.py
 plcarguments = 
 plcuid = 1000
diff --git a/doc/picontrolserver.html b/doc/picontrolserver.html
index 84552c0..2b8fcb1 100644
--- a/doc/picontrolserver.html
+++ b/doc/picontrolserver.html
@@ -12,7 +12,7 @@ Modul fuer die Verwaltung der PLC-Slave Funktionen.
 <h3 style="background-color:#FFFFFF;color:#FF0000">
 Global Attributes</h3>
 <table>
-<tr><td>__author__</td></tr><tr><td>__copyright__</td></tr><tr><td>__license__</td></tr>
+<tr><td>HASH_FAIL</td></tr><tr><td>HASH_NULL</td></tr><tr><td>__author__</td></tr><tr><td>__copyright__</td></tr><tr><td>__license__</td></tr>
 </table>
 <h3 style="background-color:#FFFFFF;color:#FF0000">
 Classes</h3>
diff --git a/eric-revpipyload.api b/eric-revpipyload.api
index ad935ce..86a5bd7 100644
--- a/eric-revpipyload.api
+++ b/eric-revpipyload.api
@@ -32,6 +32,8 @@ mqttserver.MqttServer?1(basetopic, sendinterval, broker_address, port=1883, tls_
 mqttserver.__author__?9
 mqttserver.__copyright__?9
 mqttserver.__license__?9
+picontrolserver.HASH_FAIL?7
+picontrolserver.HASH_NULL?7
 picontrolserver.RevPiSlave.check_connectedacl?4()
 picontrolserver.RevPiSlave.disconnect_all?4()
 picontrolserver.RevPiSlave.disconnect_replace_ios?4()
diff --git a/revpipyload/picontrolserver.py b/revpipyload/picontrolserver.py
index 8f9650a..ca132a6 100644
--- a/revpipyload/picontrolserver.py
+++ b/revpipyload/picontrolserver.py
@@ -11,6 +11,10 @@ from shared.ipaclmanager import IpAclManager
 from threading import Event, Thread
 from timeit import default_timer
 
+# Hashvalues
+HASH_NULL = b'\x00' * 16
+HASH_FAIL = b'\xff' * 16
+
 
 class RevPiSlave(Thread):
 
@@ -438,7 +442,6 @@ class RevPiSlaveDev(Thread):
                     proginit.logger.error(
                         "error on replace_io transfair: {0}".format(e)
                     )
-                    break
                 else:
                     continue
                 finally:
@@ -456,7 +459,7 @@ class RevPiSlaveDev(Thread):
                             # Hashwert erzeugen und senden
                             file_hash = md5(fh.read()).digest()
                     else:
-                        file_hash = b'\x00' * 16
+                        file_hash = HASH_NULL
                     proginit.logger.debug(
                         "send replace_ios hashvalue: {0}"
                         "".format(file_hash)
@@ -467,7 +470,7 @@ class RevPiSlaveDev(Thread):
                         "error on replace_ios hash value transfair: {0}"
                         "".format(e)
                     )
-                    break
+                    self._devcon.sendall(HASH_FAIL)
                 else:
                     continue
 
diff --git a/revpipyload/revpipyload.py b/revpipyload/revpipyload.py
index b44eef0..8af8049 100755
--- a/revpipyload/revpipyload.py
+++ b/revpipyload/revpipyload.py
@@ -224,6 +224,8 @@ class RevPiPyLoad():
             self.globalconfig["DEFAULT"].get("plcprogram", "none.py")
         self.plcarguments = \
             self.globalconfig["DEFAULT"].get("plcarguments", "")
+        self.plcworkdir_set_uid = self.globalconfig["DEFAULT"].getboolean(
+            "plcworkdir_set_uid", False)
         self.plcuid = \
             self.globalconfig["DEFAULT"].getint("plcuid", 65534)
         self.plcgid = \
@@ -333,6 +335,10 @@ class RevPiPyLoad():
             )
         os.chdir(self.plcworkdir)
 
+        # Workdirectory owner setzen
+        if self.plcworkdir_set_uid:
+            os.chown(self.plcworkdir, self.plcuid,  -1)
+
         # MQTT konfigurieren
         if restart_plcmqtt:
             self.stop_plcmqtt()