diff --git a/modules/juce_blocks_basics/topology/internal/juce_ConnectedDeviceGroup.cpp b/modules/juce_blocks_basics/topology/internal/juce_ConnectedDeviceGroup.cpp
index 29261dd330..b67af622a0 100644
--- a/modules/juce_blocks_basics/topology/internal/juce_ConnectedDeviceGroup.cpp
+++ b/modules/juce_blocks_basics/topology/internal/juce_ConnectedDeviceGroup.cpp
@@ -88,14 +88,20 @@ struct ConnectedDeviceGroup  : private juce::AsyncUpdater,
     ConnectedDeviceGroup (Detector& d, const juce::String& name, PhysicalTopologySource::DeviceConnection* connection)
         : detector (d), deviceName (name), deviceConnection (connection)
     {
-        deviceConnection->handleMessageFromDevice = [this] (const void* data, size_t dataSize)
-        {
-            this->handleIncomingMessage (data, dataSize);
-        };
+
 
         if (auto midiDeviceConnection = static_cast<MIDIDeviceConnection*> (deviceConnection.get()))
+        {
             depreciatedVersionReader = std::make_unique<DepreciatedVersionReader> (*midiDeviceConnection);
 
+            juce::ScopedLock lock (midiDeviceConnection->criticalSecton);
+            setMidiMessageCallback();
+        }
+        else
+        {
+            setMidiMessageCallback();
+        }
+
         startTimer (200);
         sendTopologyRequest();
     }
@@ -372,6 +378,15 @@ private:
 
     Block::UID masterBlock = 0;
 
+    //==============================================================================
+    void setMidiMessageCallback()
+    {
+        deviceConnection->handleMessageFromDevice = [this] (const void* data, size_t dataSize)
+        {
+            this->handleIncomingMessage (data, dataSize);
+        };
+    }
+
     //==============================================================================
     juce::Time lastTopologyRequestTime, lastTopologyReceiveTime;
     int numTopologyRequestsSent = 0;
diff --git a/modules/juce_blocks_basics/topology/internal/juce_DepreciatedVersionReader.cpp b/modules/juce_blocks_basics/topology/internal/juce_DepreciatedVersionReader.cpp
index 37b1a272bd..c338ad1d9c 100644
--- a/modules/juce_blocks_basics/topology/internal/juce_DepreciatedVersionReader.cpp
+++ b/modules/juce_blocks_basics/topology/internal/juce_DepreciatedVersionReader.cpp
@@ -70,10 +70,10 @@ private:
     static constexpr size_t numFirmwareApps = 3;
     BlocksProtocol::VersionNumber result[numFirmwareApps];
     MIDIDeviceConnection& deviceConnection;
-    size_t currentRequest = 0;
+    juce::Atomic<size_t> currentRequest = 0;
 
     //==============================================================================
-    bool allRequestsComplete() const { return currentRequest >= numFirmwareApps; }
+    bool allRequestsComplete() const { return currentRequest.get() >= numFirmwareApps; }
 
     //==============================================================================
     void makeNextRequest()
@@ -83,17 +83,17 @@ private:
                                                           { 0xf0, 0x00, 0x21, 0x10, 0x47, 0x03, 0x01, 0xf7 },  // Stm32
                                                           { 0xf0, 0x00, 0x21, 0x10, 0x47, 0x03, 0x03, 0xf7 }}; // Bootloader
 
-        deviceConnection.sendMessageToDevice (&requests[currentRequest][0], requestSize);
+        deviceConnection.sendMessageToDevice (&requests[currentRequest.get()][0], requestSize);
     }
 
     //==============================================================================
     void processVersionMessage (const uint8* data, const size_t size)
     {
-        if (currentRequest >= numFirmwareApps || size < 1 || size - 1 > VersionNumber::maxLength)
+        if (currentRequest.get() >= numFirmwareApps || size < 1 || size - 1 > VersionNumber::maxLength)
             return;
 
-        result[currentRequest].length = uint8 (size - 1);
-        memcpy (result[currentRequest].data, data, result[currentRequest].length);
+        result[currentRequest.get()].length = uint8 (size - 1);
+        memcpy (result[currentRequest.get()].data, data, result[currentRequest.get()].length);
 
         ++currentRequest;
 
diff --git a/modules/juce_blocks_basics/topology/internal/juce_MidiDeviceConnection.cpp b/modules/juce_blocks_basics/topology/internal/juce_MidiDeviceConnection.cpp
index 30beb56aa9..17b34d7b0b 100644
--- a/modules/juce_blocks_basics/topology/internal/juce_MidiDeviceConnection.cpp
+++ b/modules/juce_blocks_basics/topology/internal/juce_MidiDeviceConnection.cpp
@@ -63,11 +63,13 @@ struct MIDIDeviceConnection  : public PhysicalTopologySource::DeviceConnection,
 
     void addListener (Listener* l)
     {
+        juce::ScopedLock scopedLock (criticalSecton);
         listeners.add (l);
     }
 
     void removeListener (Listener* l)
     {
+        juce::ScopedLock scopedLock (criticalSecton);
         listeners.remove (l);
     }
 
@@ -90,20 +92,27 @@ struct MIDIDeviceConnection  : public PhysicalTopologySource::DeviceConnection,
 
     void handleIncomingMidiMessage (juce::MidiInput*, const juce::MidiMessage& message) override
     {
-        const auto data = message.getRawData();
-        const int dataSize = message.getRawDataSize();
-        const int bodySize = dataSize - (int) (sizeof (BlocksProtocol::roliSysexHeader) + 1);
+        juce::ScopedTryLock lock (criticalSecton);
 
-        if (bodySize > 0 && memcmp (data, BlocksProtocol::roliSysexHeader, sizeof (BlocksProtocol::roliSysexHeader)) == 0)
-            if (handleMessageFromDevice != nullptr)
-                handleMessageFromDevice (data + sizeof (BlocksProtocol::roliSysexHeader), (size_t) bodySize);
+        if (lock.isLocked())
+        {
+            const auto data = message.getRawData();
+            const int dataSize = message.getRawDataSize();
+            const int bodySize = dataSize - (int) (sizeof (BlocksProtocol::roliSysexHeader) + 1);
+
+            if (bodySize > 0 && memcmp (data, BlocksProtocol::roliSysexHeader, sizeof (BlocksProtocol::roliSysexHeader)) == 0)
+                if (handleMessageFromDevice != nullptr)
+                    handleMessageFromDevice (data + sizeof (BlocksProtocol::roliSysexHeader), (size_t) bodySize);
 
-        listeners.call ([&] (Listener& l) { l.handleIncomingMidiMessage (message); });
+            listeners.call ([&] (Listener& l) { l.handleIncomingMidiMessage (message); });
+        }
     }
 
     std::unique_ptr<juce::MidiInput> midiInput;
     std::unique_ptr<juce::MidiOutput> midiOutput;
 
+    juce::CriticalSection criticalSecton;
+
 private:
     juce::ListenerList<Listener> listeners;
     std::unique_ptr<juce::InterProcessLock> interprocessLock;