diff --git a/src/midikeyboard.cpp b/src/midikeyboard.cpp
index 0077275..2eae9d8 100644
--- a/src/midikeyboard.cpp
+++ b/src/midikeyboard.cpp
@@ -104,7 +104,7 @@ void CMIDIKeyboard::Send (const u8 *pMessage, size_t nLength, unsigned nCable)
 // Most packets will be passed straight onto the main MIDI message handler
 // but SysEx messages are multiple USB packets and so will need building up
 // before parsing.
-void CMIDIKeyboard::USBMIDIMessageHandler (unsigned nInstance, u8 *pPacket, unsigned nLength, unsigned nCable)
+void CMIDIKeyboard::USBMIDIMessageHandler (u8 *pPacket, unsigned nLength, unsigned nCable)
 {
 	if ((pPacket[0] == 0xF0) && (m_nSysExIdx == 0))
 	{
@@ -162,25 +162,25 @@ void CMIDIKeyboard::USBMIDIMessageHandler (unsigned nInstance, u8 *pPacket, unsi
 void CMIDIKeyboard::MIDIPacketHandler0 (unsigned nCable, u8 *pPacket, unsigned nLength)
 {
 	assert (s_pThis[0] != 0);
-	s_pThis[0]->USBMIDIMessageHandler (0, pPacket, nLength, nCable);
+	s_pThis[0]->USBMIDIMessageHandler (pPacket, nLength, nCable);
 }
 
 void CMIDIKeyboard::MIDIPacketHandler1 (unsigned nCable, u8 *pPacket, unsigned nLength)
 {
 	assert (s_pThis[1] != 0);
-	s_pThis[1]->USBMIDIMessageHandler (1, pPacket, nLength, nCable);
+	s_pThis[1]->USBMIDIMessageHandler (pPacket, nLength, nCable);
 }
 
 void CMIDIKeyboard::MIDIPacketHandler2 (unsigned nCable, u8 *pPacket, unsigned nLength)
 {
 	assert (s_pThis[2] != 0);
-	s_pThis[2]->USBMIDIMessageHandler (2, pPacket, nLength, nCable);
+	s_pThis[2]->USBMIDIMessageHandler (pPacket, nLength, nCable);
 }
 
 void CMIDIKeyboard::MIDIPacketHandler3 (unsigned nCable, u8 *pPacket, unsigned nLength)
 {
 	assert (s_pThis[3] != 0);
-	s_pThis[3]->USBMIDIMessageHandler (3, pPacket, nLength, nCable);
+	s_pThis[3]->USBMIDIMessageHandler (pPacket, nLength, nCable);
 }
 
 void CMIDIKeyboard::DeviceRemovedHandler (CDevice *pDevice, void *pContext)
diff --git a/src/midikeyboard.h b/src/midikeyboard.h
index cb1b476..047fa52 100644
--- a/src/midikeyboard.h
+++ b/src/midikeyboard.h
@@ -31,7 +31,7 @@
 #include <circle/types.h>
 #include <queue>
 
-#define USB_SYSEX_BUFFER_SIZE (MAX_DX7_SYSEX_LENGTH+128)
+#define USB_SYSEX_BUFFER_SIZE (MAX_DX7_SYSEX_LENGTH+128) // Allow a bit spare to handle unexpected SysEx messages
 
 class CMiniDexed;
 
@@ -56,7 +56,7 @@ private:
 
 	static void DeviceRemovedHandler (CDevice *pDevice, void *pContext);
 	
-	void USBMIDIMessageHandler (unsigned nInstance, u8 *pPacket, unsigned nLength, unsigned nCable);
+	void USBMIDIMessageHandler (u8 *pPacket, unsigned nLength, unsigned nCable);
 
 private:
 	struct TSendQueueEntry