diff --git a/Configuration.h b/Configuration.h
index 61e8d65..5da4a5b 100644
--- a/Configuration.h
+++ b/Configuration.h
@@ -24,8 +24,8 @@ Licence: GPL
 #define CONFIGURATION_H
 
 #define NAME "RepRapFirmware"
-#define VERSION "0.57d-dc42"
-#define DATE "2014-01-29"
+#define VERSION "0.57e-dc42"
+#define DATE "2014-01-30"
 #define LAST_AUTHOR "reprappro.com"
 
 // Other firmware that we might switch to be compatible with.
diff --git a/GCodes.cpp b/GCodes.cpp
index d2824a8..407dd42 100644
--- a/GCodes.cpp
+++ b/GCodes.cpp
@@ -146,14 +146,25 @@ void GCodes::Spin()
 
   if(webserver->GCodeAvailable())
   {
-	  char b = webserver->ReadGCode();
-	  if(webGCode->Put(b))
+	  int8_t i = 0;
+	  do
 	  {
-		  if(webGCode->WritingFileDirectory() != NULL)
-			  WriteGCodeToFile(webGCode);
-		  else
-			  webGCode->SetFinished(ActOnGcode(webGCode));
-	  }
+		  char b = webserver->ReadGCode();
+		  if(webGCode->Put(b))
+		  {
+			  // we have a complete gcode
+			  if(webGCode->WritingFileDirectory() != NULL)
+			  {
+				  WriteGCodeToFile(webGCode);
+			  }
+			  else
+			  {
+				  webGCode->SetFinished(ActOnGcode(webGCode));
+			  }
+			  break;	// stop after receiving a complete gcode in case we haven't finished processing it
+		  }
+		  ++i;
+	  } while ( i < 16 && webserver->GCodeAvailable());
 	  platform->ClassReport("GCodes", longWait);
 	  return;
   }
@@ -300,8 +311,6 @@ bool GCodes::Pop()
 
 void GCodes::LoadMoveBufferFromGCode(GCodeBuffer *gb, bool doingG92, bool applyLimits)
 {
-	float absE;
-
 	for(uint8_t i = 0; i < DRIVES; i++)
 	{
 	    if(i < AXES)
@@ -313,9 +322,9 @@ void GCodes::LoadMoveBufferFromGCode(GCodeBuffer *gb, bool doingG92, bool applyL
 	    	{
 	    		moveArg += moveBuffer[i];
 	    	}
-	    	if (applyLimits && axisIsHomed[i] & !doingG92)
+	    	if (applyLimits && i < 2 && axisIsHomed[i] && !doingG92)	// limit X and Y moves unless doing G92
 	    	{
-	    		if (moveArg < (i == 2 ? -5.0 : 0.0))		// limits are 0 for X, Y and -5mm for Z
+	    		if (moveArg < 0.0)
 	    		{
 	    			moveArg = 0.0;
 	    		}
@@ -339,7 +348,7 @@ void GCodes::LoadMoveBufferFromGCode(GCodeBuffer *gb, bool doingG92, bool applyL
 	          moveBuffer[i] = moveArg;
 	        else
 	        {
-	          absE = moveArg;
+	          float absE = moveArg;
 	          moveBuffer[i] = absE - lastPos[i - AXES];
 	          lastPos[i - AXES] = absE;
 	        }
@@ -876,14 +885,17 @@ char* GCodes::GetCurrentCoordinates()
 	return scratchString;
 }
 
-char* GCodes::OpenFileToWrite(char* directory, char* fileName, GCodeBuffer *gb)
+void GCodes::OpenFileToWrite(const char* directory, const char* fileName, GCodeBuffer *gb)
 {
 	fileBeingWritten = platform->GetFileStore(directory, fileName, true);
 	if(fileBeingWritten == NULL)
-		  platform->Message(HOST_MESSAGE, "Can't open GCode file for writing.\n");
+	{
+		platform->Message(HOST_MESSAGE, "Can't open GCode file for writing.\n");
+	}
 	else
+	{
 		gb->SetWritingFileDirectory(directory);
-
+	}
 	eofStringCounter = 0;
 }
 
@@ -1099,7 +1111,7 @@ bool GCodes::StandbyHeaters()
 void GCodes::SetEthernetAddress(GCodeBuffer *gb, int mCode)
 {
 	byte eth[4];
-	char* ipString = gb->GetString();
+	const char* ipString = gb->GetString();
 	uint8_t sp = 0;
 	uint8_t spp = 0;
 	uint8_t ipp = 0;
@@ -1107,9 +1119,7 @@ void GCodes::SetEthernetAddress(GCodeBuffer *gb, int mCode)
 	{
 		if(ipString[sp] == '.')
 		{
-			ipString[sp] = 0;
 			eth[ipp] = atoi(&ipString[spp]);
-			ipString[sp] = '.';
 			ipp++;
 			if(ipp > 3)
 			{
@@ -1244,9 +1254,6 @@ void GCodes::HandleReply(bool error, bool fromLine, const char* reply, char gMOr
 bool GCodes::ActOnGcode(GCodeBuffer *gb)
 {
   int code;
-  float value;
-  int iValue;
-  char* str;
   bool result = true;
   bool error = false;
   bool resend = false;
@@ -1401,9 +1408,11 @@ bool GCodes::ActOnGcode(GCodeBuffer *gb)
     	break;
 
     case 28: // Write to file
-    	str = gb->GetUnprecedentedString();
-    	OpenFileToWrite(platform->GetGCodeDir(), str, gb);
-    	snprintf(reply, STRING_LENGTH, "Writing to file: %s", str);
+    	{
+			const char* str = gb->GetUnprecedentedString();
+			OpenFileToWrite(platform->GetGCodeDir(), str, gb);
+			snprintf(reply, STRING_LENGTH, "Writing to file: %s", str);
+    	}
     	break;
 
     case 29: // End of file being written; should be intercepted before getting here
@@ -1499,12 +1508,14 @@ bool GCodes::ActOnGcode(GCodeBuffer *gb)
     	break;
 
     case 114: // Deprecated
-    	str = GetCurrentCoordinates();
-    	if(str != 0)
     	{
-    		strncpy(reply, str, STRING_LENGTH);
-    	} else
+    		const char* str = GetCurrentCoordinates();
+			if(str != 0)
+			{
+				strncpy(reply, str, STRING_LENGTH);
+			} else
     		result = false;
+    	}
     	break;
 
     case 115: // Print firmware version
@@ -1517,7 +1528,7 @@ bool GCodes::ActOnGcode(GCodeBuffer *gb)
     		reprap.GetHeat()->SetActiveTemperature(1, gb->GetFValue()); // 0 is the bed
     		reprap.GetHeat()->Activate(1);
     	}
-    	// Deliberate fall-through to case 116 here to wait for temperatures
+    	/* no break */
     case 116: // Wait for everything, especially set temperatures
     	if(!AllMovesAreFinishedAndMoveBufferIsLoaded())
     		return false;
@@ -1562,6 +1573,7 @@ bool GCodes::ActOnGcode(GCodeBuffer *gb)
     case 201: // Set axis accelerations
     	for(int8_t drive = 0; drive < DRIVES; drive++)
     	{
+    		float value;
     		if(gb->Seen(gCodeLetters[drive]))
     		{
     			value = gb->GetFValue();
@@ -1577,7 +1589,7 @@ bool GCodes::ActOnGcode(GCodeBuffer *gb)
     	{
     		if(gb->Seen(gCodeLetters[drive]))
     		{
-    			value = gb->GetFValue()*distanceScale*0.016666667; // G Code feedrates are in mm/minute; we need mm/sec;
+    			float value = gb->GetFValue()*distanceScale*0.016666667; // G Code feedrates are in mm/minute; we need mm/sec;
     			platform->SetMaxFeedrate(drive, value);
     		}
     	}
@@ -1595,7 +1607,7 @@ bool GCodes::ActOnGcode(GCodeBuffer *gb)
     	{
     		if(gb->Seen(gCodeLetters[axis]))
     		{
-    			value = gb->GetFValue()*distanceScale;
+    			float value = gb->GetFValue()*distanceScale;
     			platform->SetAxisLength(axis, value);
     		}
     	}
@@ -1606,7 +1618,7 @@ bool GCodes::ActOnGcode(GCodeBuffer *gb)
     	{
     		if(gb->Seen(gCodeLetters[axis]))
     		{
-    			value = gb->GetFValue()*distanceScale*0.016666667;
+    			float value = gb->GetFValue()*distanceScale*0.016666667;
     			platform->SetHomeFeedRate(axis, value);
     		}
     	}
@@ -1640,7 +1652,7 @@ bool GCodes::ActOnGcode(GCodeBuffer *gb)
     		SetEthernetAddress(gb, code);
     	else
     	{
-    		byte *ip = platform->IPAddress();
+    		const byte *ip = platform->IPAddress();
     		snprintf(reply, STRING_LENGTH, "IP address: %d.%d.%d.%d\n ", ip[0], ip[1], ip[2], ip[3]);
     	}
     	break;
@@ -1650,7 +1662,7 @@ bool GCodes::ActOnGcode(GCodeBuffer *gb)
     		SetEthernetAddress(gb, code);
     	else
     	{
-    		byte *nm = platform->NetMask();
+    		const byte *nm = platform->NetMask();
     		snprintf(reply, STRING_LENGTH, "Net mask: %d.%d.%d.%d\n ", nm[0], nm[1], nm[2], nm[3]);
     	}
     	break;
@@ -1660,7 +1672,7 @@ bool GCodes::ActOnGcode(GCodeBuffer *gb)
     		SetEthernetAddress(gb, code);
     	else
     	{
-    		byte *gw = platform->GateWay();
+    		const byte *gw = platform->GateWay();
     		snprintf(reply, STRING_LENGTH, "Gateway: %d.%d.%d.%d\n ", gw[0], gw[1], gw[2], gw[3]);
     	}
     	break;
@@ -1673,7 +1685,7 @@ bool GCodes::ActOnGcode(GCodeBuffer *gb)
     case 556: // Axis compensation
     	if(gb->Seen('S'))
     	{
-    		value = gb->GetFValue();
+    		float value = gb->GetFValue();
     		for(int8_t axis = 0; axis < AXES; axis++)
     			if(gb->Seen(gCodeLetters[axis]))
     				reprap.GetMove()->SetAxisCompensation(axis, gb->GetFValue()/value);
@@ -1683,7 +1695,7 @@ bool GCodes::ActOnGcode(GCodeBuffer *gb)
     case 557: // Set Z probe point coordinates
     	if(gb->Seen('P'))
     	{
-    		iValue = gb->GetIValue();
+    		int iValue = gb->GetIValue();
     		if(gb->Seen(gCodeLetters[X_AXIS]))
     			reprap.GetMove()->SetXBedProbePoint(iValue, gb->GetFValue());
     		if(gb->Seen(gCodeLetters[Y_AXIS]))
@@ -1703,18 +1715,23 @@ bool GCodes::ActOnGcode(GCodeBuffer *gb)
     	break;
 
     case 559: // Upload config.g
-    	if(gb->Seen('P'))
-    		str = gb->GetString();
-    	else
-    		str = platform->GetConfigFile();
-        OpenFileToWrite(platform->GetSysDir(), str, gb);
-        snprintf(reply, STRING_LENGTH, "Writing to file: %s", str);
+    	{
+    		const char* str;
+			if(gb->Seen('P'))
+				str = gb->GetString();
+			else
+				str = platform->GetConfigFile();
+			OpenFileToWrite(platform->GetSysDir(), str, gb);
+			snprintf(reply, STRING_LENGTH, "Writing to file: %s", str);
+    	}
     	break;
 
     case 560: // Upload reprap.htm
-         str = INDEX_PAGE;
-         OpenFileToWrite(platform->GetWebDir(), str, gb);
-         snprintf(reply, STRING_LENGTH, "Writing to file: %s", str);
+    	{
+    		const char* str = INDEX_PAGE;
+    		OpenFileToWrite(platform->GetWebDir(), str, gb);
+    		snprintf(reply, STRING_LENGTH, "Writing to file: %s", str);
+    	}
      	break;
 
     case 561:
@@ -1724,7 +1741,7 @@ bool GCodes::ActOnGcode(GCodeBuffer *gb)
     case 562: // Reset temperature fault - use with great caution
     	if(gb->Seen('P'))
     	{
-    	    iValue = gb->GetIValue();
+    	    int iValue = gb->GetIValue();
     	    reprap.GetHeat()->ResetFault(iValue);
     	}
     	break;
@@ -1755,7 +1772,7 @@ bool GCodes::ActOnGcode(GCodeBuffer *gb)
     	{
     		if(gb->Seen(gCodeLetters[i]))
     		{
-    			value = gb->GetFValue(); // mA
+    			float value = gb->GetFValue(); // mA
     			platform->SetMotorCurrent(i, value);
     		}
     	}
@@ -1826,7 +1843,7 @@ bool GCodes::ActOnGcode(GCodeBuffer *gb)
 
 // This class stores a single G Code and provides functions to allow it to be parsed
 
-GCodeBuffer::GCodeBuffer(Platform* p, char* id)
+GCodeBuffer::GCodeBuffer(Platform* p, const char* id)
 { 
   platform = p;
   identity = id;
@@ -1843,7 +1860,7 @@ void GCodeBuffer::Init()
 int GCodeBuffer::CheckSum()
 {
 	int cs = 0;
-	for(int i = 0; gcodeBuffer[i] != '*' && gcodeBuffer[i] != NULL; i++)
+	for(int i = 0; gcodeBuffer[i] != '*' && gcodeBuffer[i] != 0; i++)
 	   cs = cs ^ gcodeBuffer[i];
 	cs &= 0xff;  // Defensive programming...
 	return cs;
@@ -1864,7 +1881,7 @@ bool GCodeBuffer::Put(char c)
   {
     gcodeBuffer[gcodePointer] = 0;
     Init();
-    if(reprap.Debug() && gcodeBuffer[0]) // Don't bother with blank/comment lines
+    if(reprap.Debug() && gcodeBuffer[0] && !writingFileDirectory) // Don't bother with blank/comment lines
     {
       platform->Message(HOST_MESSAGE, identity);
       platform->Message(HOST_MESSAGE, gcodeBuffer);
@@ -1966,14 +1983,14 @@ float GCodeBuffer::GetFValue()
 // It will be the whole of the rest of the GCode string, so strings
 // should always be the last parameter.
 
-char* GCodeBuffer::GetString()
+const char* GCodeBuffer::GetString()
 {
 	if(readPointer < 0)
 	{
 		platform->Message(HOST_MESSAGE, "GCodes: Attempt to read a GCode string before a search.\n");
 		return "";
 	}
-	char* result = &gcodeBuffer[readPointer+1];
+	const char* result = &gcodeBuffer[readPointer+1];
 	readPointer = -1;
 	return result;
 }
@@ -1989,7 +2006,7 @@ char* GCodeBuffer::GetString()
 // preference use GetString() which requires the string to have
 // been preceded by a tag letter.
 
-char* GCodeBuffer::GetUnprecedentedString()
+const char* GCodeBuffer::GetUnprecedentedString()
 {
   readPointer = 0;
   while(gcodeBuffer[readPointer] && gcodeBuffer[readPointer] != ' ')
diff --git a/GCodes.h b/GCodes.h
index 878907b..30507ee 100644
--- a/GCodes.h
+++ b/GCodes.h
@@ -32,31 +32,31 @@ Licence: GPL
 class GCodeBuffer
 {
   public:
-    GCodeBuffer(Platform* p, char* id);
+    GCodeBuffer(Platform* p, const char* id);
     void Init();
     bool Put(char c);
     bool Seen(char c);
     float GetFValue();
     int GetIValue();
     long GetLValue();
-    char* GetUnprecedentedString();
-    char* GetString();
-    char* Buffer();
+    const char* GetUnprecedentedString();
+    const char* GetString();
+    const char* Buffer();
     bool Finished() const;
     void SetFinished(bool f);
-    char* WritingFileDirectory() const;
-    void SetWritingFileDirectory(char* wfd);
+    const char* WritingFileDirectory() const;
+    void SetWritingFileDirectory(const char* wfd);
     
   private:
     int CheckSum();
     Platform* platform;
     char gcodeBuffer[GCODE_LENGTH];
-    char* identity;
+    const char* identity;
     int gcodePointer;
     int readPointer;
     bool inComment;
     bool finished;
-    char* writingFileDirectory;
+    const char* writingFileDirectory;
 };
 
 //****************************************************************************************************
@@ -108,7 +108,7 @@ class GCodes
     bool StandbyHeaters();
     void SetEthernetAddress(GCodeBuffer *gb, int mCode);
     void HandleReply(bool error, bool fromLine, const char* reply, char gMOrT, int code, bool resend);
-    char* OpenFileToWrite(char* directory, char* fileName, GCodeBuffer *gb);
+    void OpenFileToWrite(const char* directory, const char* fileName, GCodeBuffer *gb);
     void WriteGCodeToFile(GCodeBuffer *gb);
     bool SendConfigToLine();
     void WriteHTMLToFile(char b, GCodeBuffer *gb);
@@ -172,7 +172,7 @@ inline int GCodeBuffer::GetIValue()
   return (int)GetLValue();
 }
 
-inline char* GCodeBuffer::Buffer()
+inline const char* GCodeBuffer::Buffer()
 {
   return gcodeBuffer;
 }
@@ -187,12 +187,12 @@ inline void GCodeBuffer::SetFinished(bool f)
   finished = f;
 }
 
-inline char* GCodeBuffer::WritingFileDirectory() const
+inline const char* GCodeBuffer::WritingFileDirectory() const
 {
 	return writingFileDirectory;
 }
 
-inline void GCodeBuffer::SetWritingFileDirectory(char* wfd)
+inline void GCodeBuffer::SetWritingFileDirectory(const char* wfd)
 {
 	writingFileDirectory = wfd;
 }
diff --git a/Heat.h b/Heat.h
index d63dd97..5b1127e 100644
--- a/Heat.h
+++ b/Heat.h
@@ -156,10 +156,7 @@ inline void Heat::SetStandbyTemperature(int8_t heater, const float& t)
 
 inline float Heat::GetStandbyTemperature(int8_t heater)
 {
-  if (heater >= 0 && heater < HEATERS)
-  {
-    return pids[heater]->GetStandbyTemperature();
-  }
+  return (heater >= 0 && heater < HEATERS) ? pids[heater]->GetStandbyTemperature() : ABS_ZERO;
 }
 
 inline float Heat::GetTemperature(int8_t heater)
diff --git a/Platform.cpp b/Platform.cpp
index a823bcb..42de134 100644
--- a/Platform.cpp
+++ b/Platform.cpp
@@ -763,7 +763,7 @@ void FileStore::Write(char b)
 	  WriteBuffer();
 }
 
-void FileStore::Write(char* b)
+void FileStore::Write(const char* b)
 {
   if(!inUse)
   {
diff --git a/Platform.h b/Platform.h
index f7b292e..5562f03 100644
--- a/Platform.h
+++ b/Platform.h
@@ -368,7 +368,7 @@ public:
 	int8_t Status(); // Returns OR of IOStatus
 	bool Read(char& b);
 	void Write(char b);
-	void Write(char* s);
+	void Write(const char* s);
 	void Close();
 	void GoToEnd(); // Position the file at the end (so you can write on the end).
 	unsigned long Length(); // File size in bytes
@@ -418,7 +418,7 @@ class Platform
   
   void Exit(); // Shut down tidily.  Calling Init after calling this should reset to the beginning
   
-  Compatibility Emulating();
+  Compatibility Emulating() const;
 
   void SetEmulating(Compatibility c);
 
@@ -439,24 +439,24 @@ class Platform
   // Communications and data storage
   
   Network* GetNetwork();
-  Line* GetLine();
+  Line* GetLine() const;
   void SetIPAddress(byte ip[]);
-  byte* IPAddress();
+  const byte* IPAddress() const;
   void SetNetMask(byte nm[]);
-  byte* NetMask();
+  const byte* NetMask() const;
   void SetGateWay(byte gw[]);
-  byte* GateWay();
+  const byte* GateWay() const;
   
   friend class FileStore;
   
   MassStorage* GetMassStorage();
   FileStore* GetFileStore(const char* directory, const char* fileName, bool write);
   void StartNetwork();
-  char* GetWebDir(); // Where the htm etc files are
-  char* GetGCodeDir(); // Where the gcodes are
-  char* GetSysDir();  // Where the system files are
-  char* GetTempDir(); // Where temporary files are
-  char* GetConfigFile(); // Where the configuration is stored (in the system dir).
+  const char* GetWebDir() const; // Where the htm etc files are
+  const char* GetGCodeDir() const; // Where the gcodes are
+  const char* GetSysDir() const;  // Where the system files are
+  const char* GetTempDir() const; // Where temporary files are
+  const char* GetConfigFile() const; // Where the configuration is stored (in the system dir).
   
   void Message(char type, const char* message);        // Send a message.  Messages may simply flash an LED, or,
                             // say, display the messages on an LCD. This may also transmit the messages to the host.
@@ -470,21 +470,21 @@ class Platform
   void Step(byte drive);
   void Disable(byte drive); // There is no drive enable; drives get enabled automatically the first time they are used.
   void SetMotorCurrent(byte drive, float current);
-  float DriveStepsPerUnit(int8_t drive);
+  float DriveStepsPerUnit(int8_t drive) const;
   void SetDriveStepsPerUnit(int8_t drive, float value);
-  float Acceleration(int8_t drive);
+  float Acceleration(int8_t drive) const;
   void SetAcceleration(int8_t drive, float value);
-  float MaxFeedrate(int8_t drive);
+  float MaxFeedrate(int8_t drive) const;
   void SetMaxFeedrate(int8_t drive, float value);
-  float InstantDv(int8_t drive);
-  float HomeFeedRate(int8_t axis);
+  float InstantDv(int8_t drive) const;
+  float HomeFeedRate(int8_t axis) const;
   void SetHomeFeedRate(int8_t axis, float value);
   EndStopHit Stopped(int8_t drive);
-  float AxisLength(int8_t axis);
+  float AxisLength(int8_t axis) const;
   void SetAxisLength(int8_t axis, float value);
-  bool HighStopButNotLow(int8_t axis);
+  bool HighStopButNotLow(int8_t axis) const;
   
-  float ZProbeStopHeight();
+  float ZProbeStopHeight() const;
   void SetZProbeStopHeight(float z);
   int ZProbe() const;
   int ZProbeOnVal() const;
@@ -496,15 +496,15 @@ class Platform
   
   float GetTemperature(int8_t heater); // Result is in degrees celsius
   void SetHeater(int8_t heater, const float& power); // power is a fraction in [0,1]
-  float PidKp(int8_t heater);
-  float PidKi(int8_t heater);
-  float PidKd(int8_t heater);
-  float FullPidBand(int8_t heater);
-  float PidMin(int8_t heater);
-  float PidMax(int8_t heater);
-  float DMix(int8_t heater);
-  bool UsePID(int8_t heater);
-  float HeatSampleTime();
+  float PidKp(int8_t heater) const;
+  float PidKi(int8_t heater) const;
+  float PidKd(int8_t heater) const;
+  float FullPidBand(int8_t heater) const;
+  float PidMin(int8_t heater) const;
+  float PidMax(int8_t heater) const;
+  float DMix(int8_t heater) const;
+  bool UsePID(int8_t heater) const;
+  float HeatSampleTime() const;
   void CoolingFan(float speed);
   //void SetHeatOn(int8_t ho); //TEMPORARY - this will go away...
 
@@ -525,7 +525,7 @@ class Platform
   Compatibility compatibility;
 
   void InitialiseInterrupts();
-  int GetRawZHeight();
+  int GetRawZHeight() const;
   
 // DRIVES
 
@@ -570,7 +570,7 @@ class Platform
   
 // HEATERS - Bed is assumed to be the first
 
-  int GetRawTemperature(byte heater);
+  int GetRawTemperature(byte heater) const;
 
   int8_t tempSensePins[HEATERS];
   int8_t heatOnPins[HEATERS];
@@ -637,7 +637,7 @@ inline void Platform::Exit()
   active = false;
 }
 
-inline Compatibility Platform::Emulating()
+inline Compatibility Platform::Emulating() const
 {
 	if(compatibility == reprapFirmware)
 		return me;
@@ -658,34 +658,34 @@ inline void Platform::SetEmulating(Compatibility c)
 
 // Where the htm etc files are
 
-inline char* Platform::GetWebDir()
+inline const char* Platform::GetWebDir() const
 {
   return webDir;
 }
 
 // Where the gcodes are
 
-inline char* Platform::GetGCodeDir()
+inline const char* Platform::GetGCodeDir() const
 {
   return gcodeDir;
 }
 
 // Where the system files are
 
-inline char* Platform::GetSysDir()
+inline const char* Platform::GetSysDir() const
 {
   return sysDir;
 }
 
 // Where the temporary files are
 
-inline char* Platform::GetTempDir()
+inline const char* Platform::GetTempDir() const
 {
   return tempDir;
 }
 
 
-inline char* Platform::GetConfigFile()
+inline const char* Platform::GetConfigFile() const
 {
   return configFile;
 }
@@ -696,7 +696,7 @@ inline char* Platform::GetConfigFile()
 
 // Drive the RepRap machine - Movement
 
-inline float Platform::DriveStepsPerUnit(int8_t drive)
+inline float Platform::DriveStepsPerUnit(int8_t drive) const
 {
   return driveStepsPerUnit[drive]; 
 }
@@ -706,7 +706,7 @@ inline void Platform::SetDriveStepsPerUnit(int8_t drive, float value)
   driveStepsPerUnit[drive] = value;
 }
 
-inline float Platform::Acceleration(int8_t drive)
+inline float Platform::Acceleration(int8_t drive) const
 {
 	return accelerations[drive];
 }
@@ -716,14 +716,14 @@ inline void Platform::SetAcceleration(int8_t drive, float value)
 	accelerations[drive] = value;
 }
 
-inline float Platform::InstantDv(int8_t drive)
+inline float Platform::InstantDv(int8_t drive) const
 {
   return instantDvs[drive]; 
 }
 
-inline bool Platform::HighStopButNotLow(int8_t axis)
+inline bool Platform::HighStopButNotLow(int8_t axis) const
 {
-	return (lowStopPins[axis] < 0)  && (highStopPins[axis] >= 0);
+	return (lowStopPins[axis] < 0) && (highStopPins[axis] >= 0);
 }
 
 inline void Platform::SetDirection(byte drive, bool direction)
@@ -783,7 +783,7 @@ inline void Platform::SetMotorCurrent(byte drive, float current)
 	mcp.setVolatileWiper(potWipes[drive], pot);
 }
 
-inline float Platform::HomeFeedRate(int8_t axis)
+inline float Platform::HomeFeedRate(int8_t axis) const
 {
   return homeFeedrates[axis];
 }
@@ -793,7 +793,7 @@ inline void Platform::SetHomeFeedRate(int8_t axis, float value)
    homeFeedrates[axis] = value;
 }
 
-inline float Platform::AxisLength(int8_t axis)
+inline float Platform::AxisLength(int8_t axis) const
 {
   return axisLengths[axis];
 }
@@ -803,7 +803,7 @@ inline void Platform::SetAxisLength(int8_t axis, float value)
   axisLengths[axis] = value;
 }
 
-inline float Platform::MaxFeedrate(int8_t drive)
+inline float Platform::MaxFeedrate(int8_t drive) const
 {
   return maxFeedrates[drive];
 }
@@ -813,7 +813,7 @@ inline void Platform::SetMaxFeedrate(int8_t drive, float value)
 	maxFeedrates[drive] = value;
 }
 
-inline int Platform::GetRawZHeight()
+inline int Platform::GetRawZHeight() const
 {
   return (zProbeType != 0) ? analogRead(zProbePin) : 0;
 }
@@ -836,7 +836,7 @@ inline int Platform::ZProbeOnVal() const
 				: 0;
 }
 
-inline float Platform::ZProbeStopHeight()
+inline float Platform::ZProbeStopHeight() const
 {
 	return zProbeStopHeight;
 }
@@ -887,55 +887,55 @@ inline void Platform::PollZHeight()
 
 // Drive the RepRap machine - Heat and temperature
 
-inline int Platform::GetRawTemperature(byte heater)
+inline int Platform::GetRawTemperature(byte heater) const
 {
   if(tempSensePins[heater] >= 0)
     return analogRead(tempSensePins[heater]);
   return 0;
 }
 
-inline float Platform::HeatSampleTime()
+inline float Platform::HeatSampleTime() const
 {
   return heatSampleTime; 
 }
 
-inline bool Platform::UsePID(int8_t heater)
+inline bool Platform::UsePID(int8_t heater) const
 {
   return usePID[heater];
 }
 
 
-inline float Platform::PidKi(int8_t heater)
+inline float Platform::PidKi(int8_t heater) const
 {
   return pidKis[heater]*heatSampleTime;
 }
 
-inline float Platform::PidKd(int8_t heater)
+inline float Platform::PidKd(int8_t heater) const
 {
   return pidKds[heater]/heatSampleTime;
 }
 
-inline float Platform::PidKp(int8_t heater)
+inline float Platform::PidKp(int8_t heater) const
 {
   return pidKps[heater];
 }
 
-inline float Platform::FullPidBand(int8_t heater)
+inline float Platform::FullPidBand(int8_t heater) const
 {
   return fullPidBand[heater];
 }
 
-inline float Platform::PidMin(int8_t heater)
+inline float Platform::PidMin(int8_t heater) const
 {
   return pidMin[heater];  
 }
 
-inline float Platform::PidMax(int8_t heater)
+inline float Platform::PidMax(int8_t heater) const
 {
   return pidMax[heater]/PidKi(heater);
 }
 
-inline float Platform::DMix(int8_t heater)
+inline float Platform::DMix(int8_t heater) const
 {
   return dMix[heater];  
 }
@@ -985,7 +985,7 @@ inline void Platform::SetIPAddress(byte ip[])
 		ipAddress[i] = ip[i];
 }
 
-inline byte* Platform::IPAddress()
+inline const byte* Platform::IPAddress() const
 {
 	return ipAddress;
 }
@@ -996,7 +996,7 @@ inline void Platform::SetNetMask(byte nm[])
 		netMask[i] = nm[i];
 }
 
-inline byte* Platform::NetMask()
+inline const byte* Platform::NetMask() const
 {
 	return netMask;
 }
@@ -1007,12 +1007,12 @@ inline void Platform::SetGateWay(byte gw[])
 		gateWay[i] = gw[i];
 }
 
-inline byte* Platform::GateWay()
+inline const byte* Platform::GateWay() const
 {
 	return gateWay;
 }
 
-inline Line* Platform::GetLine()
+inline Line* Platform::GetLine() const
 {
 	return line;
 }
diff --git a/RepRapFirmware.cpp b/RepRapFirmware.cpp
index 47cac67..a5e82c1 100644
--- a/RepRapFirmware.cpp
+++ b/RepRapFirmware.cpp
@@ -157,9 +157,8 @@ RepRap reprap;
 
 // Do nothing more in the constructor; put what you want in RepRap:Init()
 
-RepRap::RepRap()
+RepRap::RepRap() : active(false), debug(false)
 {
-  active = false;
   platform = new Platform();
   webserver = new Webserver(platform);
   gCodes = new GCodes(platform, webserver);
diff --git a/RepRapFirmware.h b/RepRapFirmware.h
index 88ce23f..27e8749 100644
--- a/RepRapFirmware.h
+++ b/RepRapFirmware.h
@@ -31,7 +31,7 @@ class Move;
 class Heat;
 class RepRap;
 
-// A single instace of the RepRap class contains all the others
+// A single instance of the RepRap class contains all the others
 
 extern RepRap reprap;
 
diff --git a/Reprap.h b/Reprap.h
index d6704db..223765c 100644
--- a/Reprap.h
+++ b/Reprap.h
@@ -32,13 +32,13 @@ class RepRap
     void Exit();
     void Interrupt();
     void Diagnostics();
-    bool Debug();
+    bool Debug() const;
     void SetDebug(bool d);
-    Platform* GetPlatform();
-    Move* GetMove();
-    Heat* GetHeat();
-    GCodes* GetGCodes();
-    Webserver* GetWebserver();  
+    Platform* GetPlatform() const;
+    Move* GetMove() const;
+    Heat* GetHeat() const;
+    GCodes* GetGCodes() const;
+    Webserver* GetWebserver() const;
     
   private:
   
@@ -51,12 +51,12 @@ class RepRap
     bool debug;
 };
 
-inline Platform* RepRap::GetPlatform() { return platform; }
-inline Move* RepRap::GetMove() { return move; }
-inline Heat* RepRap::GetHeat() { return heat; }
-inline GCodes* RepRap::GetGCodes() { return gCodes; }
-inline Webserver* RepRap::GetWebserver() { return webserver; }
-inline bool RepRap::Debug() { return debug; }
+inline Platform* RepRap::GetPlatform() const { return platform; }
+inline Move* RepRap::GetMove() const { return move; }
+inline Heat* RepRap::GetHeat() const { return heat; }
+inline GCodes* RepRap::GetGCodes() const { return gCodes; }
+inline Webserver* RepRap::GetWebserver() const { return webserver; }
+inline bool RepRap::Debug() const { return debug; }
 
 inline void RepRap::SetDebug(bool d)
 {
diff --git a/SD-image/sys/config.g b/SD-image/sys/config.g
index 5a288ae..5ef8456 100644
--- a/SD-image/sys/config.g
+++ b/SD-image/sys/config.g
@@ -1,6 +1,5 @@
 ; RepRapPro Ormerod
 ; Standard configuration G Codes
-M111 S1; Debug on
 M550 POrmerod; Set the machine's name
 M551 Preprap; Set the password
 M552 P192.168.1.14; Set the IP address
diff --git a/Webserver.cpp b/Webserver.cpp
index e8a0429..b2c187d 100644
--- a/Webserver.cpp
+++ b/Webserver.cpp
@@ -150,6 +150,7 @@ bool Webserver::LoadGcodeBuffer(const char* gc, bool convertWeb)
 	    }
 	}
 	while (c != 0);
+	return true;
 }
 
 // Process a null-terminated gcode
diff --git a/network/ethernet_sam.c b/network/ethernet_sam.c
index c726419..c92d2d1 100644
--- a/network/ethernet_sam.c
+++ b/network/ethernet_sam.c
@@ -270,7 +270,7 @@ static void ethernet_configure_interface(unsigned char ipAddress[], unsigned cha
 /** \brief Create ethernet task, for ethernet management.
  *
  */
-void init_ethernet(unsigned char ipAddress[], unsigned char netMask[], unsigned char gateWay[])
+void init_ethernet(const unsigned char ipAddress[], const unsigned char netMask[], const unsigned char gateWay[])
 {
 	/* Initialize lwIP */
 	lwip_init();
diff --git a/network/ethernet_sam.h b/network/ethernet_sam.h
index 28b1db2..daf3c68 100644
--- a/network/ethernet_sam.h
+++ b/network/ethernet_sam.h
@@ -62,7 +62,7 @@ bool status_link_up();//*****************************AB
  */
 //void init_ethernet(void);
 
-void init_ethernet(unsigned char ipAddress[], unsigned char netMask[], unsigned char gateWay[]);
+void init_ethernet(const unsigned char ipAddress[], const unsigned char netMask[], const unsigned char gateWay[]);
 
 struct netif* GetConfiguration();