diff --git a/IO_RS485.cpp b/IO_RS485.cpp
index f3cbfc9..f8bc4f9 100644
--- a/IO_RS485.cpp
+++ b/IO_RS485.cpp
@@ -154,6 +154,7 @@ if (taskCnt > 0) {
           }
         } while (micros() - startMicros <= 500 && len < 256);
         if (crcGood(responseBuffer,sizeof(responseBuffer)-2)) {
+          if (!testAndStripMasterFlag(responseBuffer)) DIAG(F("Forgen RS485 Device! no master flag from node %d"),_currentNode->getNodeID());
           if (responseBuffer[0] == EXIORDY) {
           } else {
             DIAG(F("EX-IOExpander485 Vpin %u cannot be used as a digital input pin"), (int)taskData[3]);
@@ -196,6 +197,7 @@ if (taskCnt > 0) {
       } while (micros() - startMicros <= 500 && len < 256);
 
       if (crcGood(responseBuffer,sizeof(responseBuffer)-2)) {
+        if (!testAndStripMasterFlag(responseBuffer)) DIAG(F("Forgen RS485 Device! no master flag from node %d"),_currentNode->getNodeID());
         if (responseBuffer[0] != EXIORDY) {
           DIAG(F("EX-IOExpander485: Vpin %u on node %d cannot be used as an analogue input pin"), (int) taskData[3], (int) taskData[0]);
         }
@@ -234,6 +236,7 @@ if (taskCnt > 0) {
         }
       } while (micros() - startMicros <= 500 && len < 256);
       if (crcGood(responseBuffer,sizeof(responseBuffer)-2)) {
+        if (!testAndStripMasterFlag(responseBuffer)) DIAG(F("Forgen RS485 Device! no master flag from node %d"),_currentNode->getNodeID());
         if (responseBuffer[0] != EXIORDY) {
           DIAG(F("EX-IOExpander485 Vpin %u cannot be used as a digital output pin"), (int)taskData[3]);
         }
@@ -280,10 +283,11 @@ if (taskCnt > 0) {
         }
       } while (micros() - startMicros <= 500 && len < 256);
       if (!crcGood(responseBuffer,sizeof(responseBuffer)-2)) {
-         DIAG(F("EX-IOExpander485 node %d CRC Error"), (int) taskData[0]);
-         flagOK = false;
+        DIAG(F("EX-IOExpander485 node %d CRC Error"), (int) taskData[0]);
+        flagOK = false;
         _deviceState = DEVSTATE_FAILED;
       } else {
+        if (!testAndStripMasterFlag(responseBuffer)) DIAG(F("Forgen RS485 Device! no master flag from node %d"),_currentNode->getNodeID());
         if (responseBuffer[0] != EXIORDY) {
           DIAG(F("EX-IOExpander485 Vpin %u cannot be used as a servo/PWM pin"), (int) taskData[3]);
         }
@@ -324,6 +328,7 @@ if (taskCnt > 0) {
           DIAG(F("EX-IOExpander485 CRC error on node %d"), _currentNode->getNodeID());
           flagOK = false;
         }
+        if (!testAndStripMasterFlag(_currentNode->_digitalInputStates)) DIAG(F("Forgen RS485 Device! no master flag from node %d"),_currentNode->getNodeID());
         if (!waitReceive) _refreshOperation++;
         _lastDigitalRead = currentMicros;
         _readState = RDS_DIGITAL;
@@ -360,6 +365,7 @@ if (taskCnt > 0) {
           DIAG(F("EX-IOExpander485 CRC error on node %d"), _currentNode->getNodeID());
           flagOK = false;
         }
+        if (!testAndStripMasterFlag(_currentNode->_digitalInputStates)) DIAG(F("Forgen RS485 Device! no master flag from node %d"),_currentNode->getNodeID());
         if (!waitReceive) _refreshOperation = 0;
         _lastAnalogueRead = currentMicros;
         _readState = RDS_ANALOGUE;
@@ -406,7 +412,7 @@ RS485node::RS485node(VPIN firstVpin, int nPins, uint8_t nodeID) {
   _nPins = nPins;
   _busNo = 0;
   _nodeID = nodeID;
-  if (_nodeID > 255) _nodeID = 255;
+  if (_nodeID > 254) _nodeID = 254;
 
   // Add this device to HAL device list
   IODevice::addDevice(this);
diff --git a/IO_RS485.h b/IO_RS485.h
index e562959..b21b69e 100644
--- a/IO_RS485.h
+++ b/IO_RS485.h
@@ -37,7 +37,7 @@
  * 
  * firstVPIN = first vpin in block allocated to this device
  * numVPINs = number of vpins
- * nodeID = 0-255
+ * nodeID = 0-254
  */
 
 #ifndef IO_RS485_H
@@ -170,7 +170,8 @@ public:
         len++;
       }
     } while (micros() - startMicros <= 500 && len < 256);
-    if (receiveBuffer[0] == EXIOPINS && bus->crcGood(receiveBuffer,sizeof(receiveBuffer)-2)) {
+    if (receiveBuffer[1] == EXIOPINS && bus->crcGood(receiveBuffer,sizeof(receiveBuffer)-2)) {
+      if (!bus->testAndStripMasterFlag(receiveBuffer)) DIAG(F("Forgen RS485 Device! no master flag from node %d"),_nodeID);
       _numDigitalPins = receiveBuffer[1];
       _numAnaloguePins = receiveBuffer[2];
 
@@ -241,6 +242,7 @@ public:
       }
     } while (micros() - startMicros <= 500 && len < 256);
     if (bus->crcGood(receiveBuffer,sizeof(receiveBuffer)-2)) {
+      if (!bus->testAndStripMasterFlag(receiveBuffer)) DIAG(F("Forgen RS485 Device! no master flag from node %d"),_nodeID);
       for (int i = 0; i < _numAnaloguePins; i++) {
         _analoguePinMap[i] = receiveBuffer[i];
       }
@@ -267,6 +269,7 @@ public:
       }
     } while (micros() - startMicros <= 500 && len < 256);
     if (bus->crcGood(versionBuffer,sizeof(versionBuffer)-2)) {
+      if (!bus->testAndStripMasterFlag(versionBuffer)) DIAG(F("Forgen RS485 Device! no master flag from node %d"),_nodeID);
       _majorVer = versionBuffer[0];
       _minorVer = versionBuffer[1];
       _patchVer = versionBuffer[2];
@@ -420,6 +423,11 @@ public:
   int8_t _txPin;
   int taskCnt = 0;
   HardwareSerial *_serialD;
+  bool testAndStripMasterFlag(uint8_t *buf) {
+    if (buf[0] != 0xFF) return false; // why did we not get a master flag? bad node?
+    for (int i = 0; i < sizeof(buf)-1; i++) buf[i] = buf[i+1]; // shift array to begining
+    return true;
+  }
   void addTask(int nodeID, int taskNum, int paramCnt, int *param[]) {
     taskCnt++;
     tasks[taskCnt][0] = nodeID;