diff --git a/src/Config.cpp b/src/Config.cpp
index 35b5153f..78d9302e 100644
--- a/src/Config.cpp
+++ b/src/Config.cpp
@@ -155,7 +155,13 @@ void resetConfig()
     Servos::Clear();
 #endif
 #if MF_STEPPER_SUPPORT == 1
+#if defined(STEPPER_ON_2ND_CORE) && defined(ARDUINO_ARCH_RP2040)
+    Stepper::stopUpdate2ndCore(true);
+#endif
     Stepper::Clear();
+#if defined(STEPPER_ON_2ND_CORE) && defined(ARDUINO_ARCH_RP2040)
+    Stepper::stopUpdate2ndCore(false);
+#endif
 #endif
 #if MF_LCD_SUPPORT == 1
     LCDDisplay::Clear();
@@ -173,7 +179,13 @@ void resetConfig()
     DigInMux::Clear();
 #endif
 #if MF_CUSTOMDEVICE_SUPPORT == 1
+#if defined(USE_2ND_CORE) && defined(ARDUINO_ARCH_RP2040)
+    CustomDevice::stopUpdate2ndCore(true);
+#endif
     CustomDevice::Clear();
+#if defined(USE_2ND_CORE) && defined(ARDUINO_ARCH_RP2040)
+    CustomDevice::stopUpdate2ndCore(false);
+#endif
 #endif
     configLengthEEPROM = 0;
     configActivated    = false;
diff --git a/src/MF_CustomDevice/CustomDevice.cpp b/src/MF_CustomDevice/CustomDevice.cpp
index 0d0cafb3..3d166719 100644
--- a/src/MF_CustomDevice/CustomDevice.cpp
+++ b/src/MF_CustomDevice/CustomDevice.cpp
@@ -1,7 +1,7 @@
 #include "mobiflight.h"
 #include "CustomDevice.h"
 #include "MFCustomDevice.h"
-#if defined(USE_2ND_CORE)
+#if defined(USE_2ND_CORE) && defined(ARDUINO_ARCH_RP2040)
 #include <FreeRTOS.h>
 #endif
 
@@ -92,7 +92,7 @@ namespace CustomDevice
         int16_t messageID = cmdMessenger.readInt16Arg();  // get the messageID number
         char   *output    = cmdMessenger.readStringArg(); // get the pointer to the new raw string
         cmdMessenger.unescape(output);                    // and unescape the string if escape characters are used
-#if defined(USE_2ND_CORE)
+#if defined(USE_2ND_CORE) && defined(ARDUINO_ARCH_RP2040)
         // copy the message, could get be overwritten from the next message while processing on 2nd core
         strncpy(payload, output, SERIAL_RX_BUFFER_SIZE);
         // wait for 2nd core
@@ -117,14 +117,31 @@ namespace CustomDevice
     {
         for (uint8_t i = 0; i < customDeviceRegistered; ++i) {
             if (state)
-                customDevice[i].set(MESSAGEID_POWERSAVINGMODE, (char*)"1");
+                customDevice[i].set(MESSAGEID_POWERSAVINGMODE, (char *)"1");
             else
-                customDevice[i].set(MESSAGEID_POWERSAVINGMODE, (char*)"0");
+                customDevice[i].set(MESSAGEID_POWERSAVINGMODE, (char *)"0");
         }
     }
+
+#if defined(STEPPER_ON_2ND_CORE) && defined(ARDUINO_ARCH_RP2040)
+    void stopUpdate2ndCore(bool stop)
+    {
+        // wait for 2nd core
+        rp2040.fifo.pop();
+        // send command to stop/start updating to 2nd core
+        // negative device numbers are for commands to 2nd core
+        rp2040.fifo.push(START_STOP_2ND_CORE);
+        // send stop/start
+        rp2040.fifo.push(stop);
+        // communication is always done using 3 messages
+        rp2040.fifo.push(0);
+        // wait for execution of command
+        rp2040.fifo.pop();
+    }
+#endif
 } // end of namespace
 
-#if defined(USE_2ND_CORE)
+#if defined(USE_2ND_CORE) && defined(ARDUINO_ARCH_RP2040)
 /* **********************************************************************************
     This will run the set() function from the custom device on the 2nd core
     Be aware NOT to use the function calls from the Pico SDK!
@@ -140,45 +157,45 @@ void setup1()
 
 void loop1()
 {
-    uint8_t device;
+    int16_t device;
     int16_t messageID;
     char   *payload;
+    bool    stopUpdating = false;
 #ifdef MF_CUSTOMDEVICE_POLL_MS
     uint32_t lastMillis = 0;
 #endif
 
     while (1) {
-#ifndef MF_CUSTOMDEVICE_POLL_MS
-        // For now I don't know the reason why this is required.
-        // It might be that getting the stop command from the 1st core
-        // needs some idle time. If it is not used the 1st core stops when
-        // writing to the EEPROM which stops the 2nd core
-        delayMicroseconds(1);
-#endif  
 #ifdef MF_CUSTOMDEVICE_POLL_MS
         if (millis() - lastMillis >= MF_CUSTOMDEVICE_POLL_MS) {
 #endif
-            for (int i = 0; i != CustomDevice::customDeviceRegistered; i++) {
 #if defined(MF_CUSTOMDEVICE_HAS_UPDATE)
+            for (int i = 0; i < CustomDevice::customDeviceRegistered && !stopUpdating; i++) {
                 CustomDevice::customDevice[i].update();
-#endif
-                if (rp2040.fifo.available() == 3) {
-                    // Hmhm, how to get the function pointer to a function from class??
-                    // int32_t (*func)(int16_t, char*) = (int32_t(*)(int16_t, char*)) rp2040.fifo.pop();
-                    device    = (uint8_t)rp2040.fifo.pop();
-                    messageID = (int16_t)rp2040.fifo.pop();
-                    payload   = (char *)rp2040.fifo.pop();
-                    // (*func)(messageID, payload);
-                    CustomDevice::customDevice[device].set(messageID, payload);
-                    // send ready for next message to 1st core
-                    rp2040.fifo.push(true);
-                }
-
             }
+#endif
 #ifdef MF_CUSTOMDEVICE_POLL_MS
             lastMillis = millis();
         }
 #endif
+        if (rp2040.fifo.available() == 3) {
+            // Hmhm, how to get the function pointer to a function from class??
+            // int32_t (*func)(int16_t, char*) = (int32_t(*)(int16_t, char*)) rp2040.fifo.pop();
+            device    = (int16_t)rp2040.fifo.pop();
+            messageID = (int16_t)rp2040.fifo.pop();
+            payload   = (char *)rp2040.fifo.pop();
+            if (device == -1) {
+                stopUpdating = (bool)messageID;
+                // inform core 0 that command has been executed
+                // it's additional needed in this case
+                rp2040.fifo.push(true);
+            } else {
+                // (*func)(messageID, payload);
+                CustomDevice::customDevice[device].set(messageID, payload);
+            }
+            // send ready for next message to 1st core
+            rp2040.fifo.push(true);
+        }
     }
 }
 #endif
diff --git a/src/MF_CustomDevice/CustomDevice.h b/src/MF_CustomDevice/CustomDevice.h
index 5c2abff8..58d827d3 100644
--- a/src/MF_CustomDevice/CustomDevice.h
+++ b/src/MF_CustomDevice/CustomDevice.h
@@ -2,10 +2,15 @@
 
 namespace CustomDevice
 {
+    #define START_STOP_2ND_CORE -1
+
     bool setupArray(uint16_t count);
     void Add(uint16_t adrPin, uint16_t adrType, uint16_t adrConfig, bool configFromFlash);
     void Clear();
     void update();
     void OnSet();
     void PowerSave(bool state);
+#if defined(STEPPER_ON_2ND_CORE) && defined(ARDUINO_ARCH_RP2040)
+    void stopUpdate2ndCore(bool stop);
+#endif
 }
\ No newline at end of file
diff --git a/src/MF_Stepper/Stepper.cpp b/src/MF_Stepper/Stepper.cpp
index ed2a5c4d..e6988f52 100644
--- a/src/MF_Stepper/Stepper.cpp
+++ b/src/MF_Stepper/Stepper.cpp
@@ -7,7 +7,7 @@
 #include "mobiflight.h"
 #include "MFStepper.h"
 #include "Stepper.h"
-#if defined(STEPPER_ON_2ND_CORE)
+#if defined(STEPPER_ON_2ND_CORE) && defined(ARDUINO_ARCH_RP2040)
 #include <FreeRTOS.h>
 #endif
 
@@ -20,7 +20,8 @@ namespace Stepper
     enum {
         FUNC_MOVETO = 1,
         FUNC_ZETZERO,
-        FUNC_SPEEDACCEL
+        FUNC_SPEEDACCEL,
+        START_STOP_2ND_CORE
     };
 #endif
 
@@ -71,7 +72,7 @@ namespace Stepper
 
         if (stepper >= steppersRegistered)
             return;
-#if defined(STEPPER_ON_2ND_CORE)
+#if defined(STEPPER_ON_2ND_CORE) && defined(ARDUINO_ARCH_RP2040)
         // wait for 2nd core
         rp2040.fifo.pop();
         rp2040.fifo.push(FUNC_MOVETO);
@@ -98,7 +99,7 @@ namespace Stepper
 
         if (stepper >= steppersRegistered)
             return;
-#if defined(STEPPER_ON_2ND_CORE)
+#if defined(STEPPER_ON_2ND_CORE) && defined(ARDUINO_ARCH_RP2040)
         // wait for 2nd core
         rp2040.fifo.pop();
         rp2040.fifo.push(FUNC_ZETZERO);
@@ -118,7 +119,7 @@ namespace Stepper
 
         if (stepper >= steppersRegistered)
             return;
-#if defined(STEPPER_ON_2ND_CORE)
+#if defined(STEPPER_ON_2ND_CORE) && defined(ARDUINO_ARCH_RP2040)
         rp2040.fifo.pop(); // wait for 2nd core
         rp2040.fifo.push(FUNC_SPEEDACCEL);
         rp2040.fifo.push(stepper);
@@ -146,9 +147,24 @@ namespace Stepper
         }
     }
 
+#if defined(STEPPER_ON_2ND_CORE) && defined(ARDUINO_ARCH_RP2040)
+    void stopUpdate2ndCore(bool stop)
+    {
+        // wait for 2nd core
+        rp2040.fifo.pop();
+        // send command to stop/start updating to 2nd core
+        rp2040.fifo.push(START_STOP_2ND_CORE);
+        // communication is always done using 4 messages
+        rp2040.fifo.push(0);
+        rp2040.fifo.push(stop);
+        rp2040.fifo.push(0);
+        // wait for execution of command
+        rp2040.fifo.pop();
+    }
+#endif
 } // namespace
 
-#if defined(STEPPER_ON_2ND_CORE)
+#if defined(STEPPER_ON_2ND_CORE) && defined(ARDUINO_ARCH_RP2040)
 /* **********************************************************************************
     This will run the set() function from the custom device on the 2nd core
     Be aware NOT to use the function calls from the Pico SDK!
@@ -158,32 +174,40 @@ namespace Stepper
 ********************************************************************************** */
 void setup1()
 {
-    rp2040.fifo.push(true); // inform core 1 to be ready
+    // send "ready" message to 1st core
+    rp2040.fifo.push(true);
 }
 
 void loop1()
 {
-    uint8_t  command, stepper;
+    uint8_t command, stepper;
     int32_t param1, param2;
+    bool    stopUpdating = false;
 
     while (1) {
-        for (uint8_t i = 0; i < Stepper::steppersRegistered; ++i) {
+        for (uint8_t i = 0; i < Stepper::steppersRegistered && !stopUpdating; ++i) {
             Stepper::steppers[i].update();
-            if (rp2040.fifo.available()) {
-                command = (uint8_t)rp2040.fifo.pop();
-                stepper = (uint8_t)rp2040.fifo.pop();
-                param1  = (int32_t)rp2040.fifo.pop();
-                param2  = (int32_t)rp2040.fifo.pop();
-                if (command == Stepper::FUNC_MOVETO) {
-                    Stepper::steppers[stepper].moveTo(param1);
-                } else if (command == Stepper::FUNC_ZETZERO) {
-                    Stepper::steppers[stepper].setZero();
-                } else if (command == Stepper::FUNC_SPEEDACCEL) {
-                    Stepper::steppers[stepper].setMaxSpeed(param1);
-                    Stepper::steppers[stepper].setAcceleration(param2);
-                }
-                rp2040.fifo.push(true); // inform core 1 to be ready for next command
+        }
+        if (rp2040.fifo.available()) {
+            command = (uint8_t)rp2040.fifo.pop();
+            stepper = (uint8_t)rp2040.fifo.pop();
+            param1  = (int32_t)rp2040.fifo.pop();
+            param2  = (int32_t)rp2040.fifo.pop();
+            if (command == Stepper::FUNC_MOVETO) {
+                Stepper::steppers[stepper].moveTo(param1);
+            } else if (command == Stepper::FUNC_ZETZERO) {
+                Stepper::steppers[stepper].setZero();
+            } else if (command == Stepper::FUNC_SPEEDACCEL) {
+                Stepper::steppers[stepper].setMaxSpeed(param1);
+                Stepper::steppers[stepper].setAcceleration(param2);
+            } else if (command == Stepper::START_STOP_2ND_CORE) {
+                stopUpdating = (bool)param1;
+                // inform core 0 that command has been executed
+                // it's additional needed in this case
+                rp2040.fifo.push(true);
             }
+            // send ready for next message to 1st core
+            rp2040.fifo.push(true);
         }
     }
 }
diff --git a/src/MF_Stepper/Stepper.h b/src/MF_Stepper/Stepper.h
index fc7e797d..59da4822 100644
--- a/src/MF_Stepper/Stepper.h
+++ b/src/MF_Stepper/Stepper.h
@@ -17,6 +17,9 @@ namespace Stepper
     void update();
     void OnSetSpeedAccel();
     void PowerSave(bool state);
+#if defined(STEPPER_ON_2ND_CORE) && defined(ARDUINO_ARCH_RP2040)
+    void stopUpdate2ndCore(bool stop);
+#endif
 }
 
 // Stepper.h
\ No newline at end of file