diff --git a/Demos/Device/ClassDriver/MassStorage/Lib/DataflashManager.c b/Demos/Device/ClassDriver/MassStorage/Lib/DataflashManager.c
index 5f12d02b438193313b656dc601571fe80d5e4396..3858d387323500fe04e22d75317701d14afb108e 100644
--- a/Demos/Device/ClassDriver/MassStorage/Lib/DataflashManager.c
+++ b/Demos/Device/ClassDriver/MassStorage/Lib/DataflashManager.c
@@ -69,11 +69,8 @@ void DataflashManager_WriteBlocks(USB_ClassInfo_MS_Device_t* MSInterfaceInfo, co
 	Dataflash_SendAddressBytes(0, CurrDFPageByte);
 
 	/* Wait until endpoint is ready before continuing */
-	while (!(Endpoint_IsReadWriteAllowed()))
-	{
-		if (USB_DeviceState == DEVICE_STATE_Unattached)
-		  return;
-	}
+	if (Endpoint_WaitUntilReady())
+	  return;
 
 	while (TotalBlocks)
 	{
@@ -89,11 +86,8 @@ void DataflashManager_WriteBlocks(USB_ClassInfo_MS_Device_t* MSInterfaceInfo, co
 				Endpoint_ClearOUT();
 				
 				/* Wait until the host has sent another packet */
-				while (!(Endpoint_IsReadWriteAllowed()))
-				{
-					if (USB_DeviceState == DEVICE_STATE_Unattached)
-					  return;
-				}
+				if (Endpoint_WaitUntilReady())
+				  return;
 			}
 
 			/* Check if end of dataflash page reached */
@@ -205,11 +199,8 @@ void DataflashManager_ReadBlocks(USB_ClassInfo_MS_Device_t* MSInterfaceInfo, con
 	Dataflash_SendByte(0x00);
 	
 	/* Wait until endpoint is ready before continuing */
-	while (!(Endpoint_IsReadWriteAllowed()))
-	{
-		if (USB_DeviceState == DEVICE_STATE_Unattached)
-		  return;
-	}
+	if (Endpoint_WaitUntilReady())
+	  return;
 	
 	while (TotalBlocks)
 	{
@@ -225,11 +216,8 @@ void DataflashManager_ReadBlocks(USB_ClassInfo_MS_Device_t* MSInterfaceInfo, con
 				Endpoint_ClearIN();
 				
 				/* Wait until the endpoint is ready for more data */
-				while (!(Endpoint_IsReadWriteAllowed()))
-				{
-					if (USB_DeviceState == DEVICE_STATE_Unattached)
-					  return;
-				}
+				if (Endpoint_WaitUntilReady())
+				  return;
 			}
 			
 			/* Check if end of dataflash page reached */
diff --git a/Demos/Device/ClassDriver/MassStorage/MassStorage.h b/Demos/Device/ClassDriver/MassStorage/MassStorage.h
index e6b2bf99f4321551eeb94235bb853b90f01d8e31..930e8f4cb063fab5d62bacf65914ab7ac9114993 100644
--- a/Demos/Device/ClassDriver/MassStorage/MassStorage.h
+++ b/Demos/Device/ClassDriver/MassStorage/MassStorage.h
@@ -70,7 +70,7 @@
 		#define LEDMASK_USB_BUSY         (LEDS_LED2)
 		
 		/** Total number of logical drives within the device - must be non-zero. */
-		#define TOTAL_LUNS                2
+		#define TOTAL_LUNS                1
 		
 		/** Blocks in each LUN, calculated from the total capacity divided by the total number of Logical Units in the device. */
 		#define LUN_MEDIA_BLOCKS         (VIRTUAL_MEMORY_BLOCKS / TOTAL_LUNS)
diff --git a/Demos/Device/LowLevel/CDC/CDC.c b/Demos/Device/LowLevel/CDC/CDC.c
index 9ee744ea044c4cba351cb49ed12680a748cf1605..12cd8c40f9041436118b174643ca5b27fe531e48 100644
--- a/Demos/Device/LowLevel/CDC/CDC.c
+++ b/Demos/Device/LowLevel/CDC/CDC.c
@@ -62,11 +62,8 @@ static int CDC_putchar(char c, FILE *stream)
 	if (!(LineEncoding.BaudRateBPS))
 	  return -1;
 	
-	while (!(Endpoint_IsReadWriteAllowed()))
-	{
-		if (USB_DeviceState != DEVICE_STATE_Configured)
-		  return -1;
-	}
+	if (Endpoint_WaitUntilReady())
+	  return -1;
 
 	Endpoint_Write_Byte(c);
 	Endpoint_ClearIN();
@@ -85,11 +82,8 @@ static int CDC_getchar(FILE *stream)
 	
 	for (;;)
 	{
-		while (!(Endpoint_IsReadWriteAllowed()))
-		{
-			if (USB_DeviceState != DEVICE_STATE_Configured)
-			  return -1;
-		}
+		if (Endpoint_WaitUntilReady())
+		  return -1;
 	
 		if (!(Endpoint_BytesInEndpoint()))
 		{
@@ -327,11 +321,7 @@ void CDC_Task(void)
 		if (IsFull)
 		{
 			/* Wait until the endpoint is ready for another packet */
-			while (!(Endpoint_IsINReady()))
-			{
-				if (USB_DeviceState == DEVICE_STATE_Unattached)
-				  return;
-			}
+			Endpoint_WaitUntilReady();
 			
 			/* Send an empty packet to ensure that the host does not buffer data sent to it */
 			Endpoint_ClearIN();
diff --git a/Demos/Device/LowLevel/DualCDC/DualCDC.c b/Demos/Device/LowLevel/DualCDC/DualCDC.c
index c49a1ad85bd3785db5cd62b7892c35b5fa3388dd..7a84c8dcda2667b0a696f6993807a7919520e945 100644
--- a/Demos/Device/LowLevel/DualCDC/DualCDC.c
+++ b/Demos/Device/LowLevel/DualCDC/DualCDC.c
@@ -274,11 +274,7 @@ void CDC1_Task(void)
 		Endpoint_ClearIN();
 
 		/* Wait until the endpoint is ready for another packet */
-		while (!(Endpoint_IsINReady()))
-		{
-			if (USB_DeviceState == DEVICE_STATE_Unattached)
-			  return;
-		}
+		Endpoint_WaitUntilReady();
 		
 		/* Send an empty packet to ensure that the host does not buffer data sent to it */
 		Endpoint_ClearIN();
@@ -329,11 +325,7 @@ void CDC2_Task(void)
 		Endpoint_ClearIN();
 
 		/* Wait until the endpoint is ready for the next packet */
-		while (!(Endpoint_IsINReady()))
-		{
-			if (USB_DeviceState == DEVICE_STATE_Unattached)
-			  return;
-		}
+		Endpoint_WaitUntilReady();
 
 		/* Send an empty packet to prevent host buffering */
 		Endpoint_ClearIN();
diff --git a/Demos/Device/LowLevel/MassStorage/Lib/DataflashManager.c b/Demos/Device/LowLevel/MassStorage/Lib/DataflashManager.c
index 2bd03c98d925caab5bf263200ec00a6fde494a29..9cd0279d627ef254a44a1648f3bfee4b2f73c72c 100644
--- a/Demos/Device/LowLevel/MassStorage/Lib/DataflashManager.c
+++ b/Demos/Device/LowLevel/MassStorage/Lib/DataflashManager.c
@@ -68,11 +68,8 @@ void DataflashManager_WriteBlocks(const uint32_t BlockAddress, uint16_t TotalBlo
 	Dataflash_SendAddressBytes(0, CurrDFPageByte);
 
 	/* Wait until endpoint is ready before continuing */
-	while (!(Endpoint_IsReadWriteAllowed()))
-	{
-		if (USB_DeviceState == DEVICE_STATE_Unattached)
-		  return;
-	}
+	if (Endpoint_WaitUntilReady())
+	  return;
 	
 	while (TotalBlocks)
 	{
@@ -88,11 +85,8 @@ void DataflashManager_WriteBlocks(const uint32_t BlockAddress, uint16_t TotalBlo
 				Endpoint_ClearOUT();
 				
 				/* Wait until the host has sent another packet */
-				while (!(Endpoint_IsReadWriteAllowed()))
-				{
-					if (USB_DeviceState == DEVICE_STATE_Unattached)
-					  return;
-				}
+				if (Endpoint_WaitUntilReady())
+				  return;
 			}
 
 			/* Check if end of dataflash page reached */
@@ -203,11 +197,8 @@ void DataflashManager_ReadBlocks(const uint32_t BlockAddress, uint16_t TotalBloc
 	Dataflash_SendByte(0x00);
 	
 	/* Wait until endpoint is ready before continuing */
-	while (!(Endpoint_IsReadWriteAllowed()))
-	{
-		if (USB_DeviceState == DEVICE_STATE_Unattached)
-		  return;
-	}
+	if (Endpoint_WaitUntilReady())
+	  return;
 	
 	while (TotalBlocks)
 	{
@@ -223,11 +214,8 @@ void DataflashManager_ReadBlocks(const uint32_t BlockAddress, uint16_t TotalBloc
 				Endpoint_ClearIN();
 				
 				/* Wait until the endpoint is ready for more data */
-				while (!(Endpoint_IsReadWriteAllowed()))
-				{
-					if (USB_DeviceState == DEVICE_STATE_Unattached)
-					  return;
-				}
+				if (Endpoint_WaitUntilReady())
+				  return;
 			}
 			
 			/* Check if end of dataflash page reached */
diff --git a/Demos/Device/LowLevel/MassStorage/MassStorage.h b/Demos/Device/LowLevel/MassStorage/MassStorage.h
index 868daf09a633f475fcb7418441fdf897bc3240b5..65407c8c14a525f17535291a9c2e0ac605ca8137 100644
--- a/Demos/Device/LowLevel/MassStorage/MassStorage.h
+++ b/Demos/Device/LowLevel/MassStorage/MassStorage.h
@@ -64,7 +64,7 @@
 		/** Total number of Logical Units (drives) in the device. The total device capacity is shared equally between
 		 *  each drive - this can be set to any positive non-zero amount.
 		 */
-		#define TOTAL_LUNS                 2
+		#define TOTAL_LUNS                 1
 		
 		/** Blocks in each LUN, calculated from the total capacity divided by the total number of Logical Units in the device. */
 		#define LUN_MEDIA_BLOCKS           (VIRTUAL_MEMORY_BLOCKS / TOTAL_LUNS)    
diff --git a/Demos/Device/LowLevel/USBtoSerial/USBtoSerial.c b/Demos/Device/LowLevel/USBtoSerial/USBtoSerial.c
index bb1b4da2d3ca8cbebe84e4d43740291d6db2b73d..736c0af10bbb6b1b902c2de2ebc9c5ebcbdec471 100644
--- a/Demos/Device/LowLevel/USBtoSerial/USBtoSerial.c
+++ b/Demos/Device/LowLevel/USBtoSerial/USBtoSerial.c
@@ -263,11 +263,7 @@ void CDC_Task(void)
 	if ((Tx_Buffer.Elements) && LineEncoding.BaudRateBPS)
 	{
 		/* Wait until Serial Tx Endpoint Ready for Read/Write */
-		while (!(Endpoint_IsReadWriteAllowed()))
-		{
-			if (USB_DeviceState == DEVICE_STATE_Unattached)
-			  return;
-		}
+		Endpoint_WaitUntilReady();
 		
 		/* Write the bytes from the buffer to the endpoint while space is available */
 		while (Tx_Buffer.Elements && Endpoint_IsReadWriteAllowed())
@@ -287,11 +283,7 @@ void CDC_Task(void)
 		if (IsFull && !(Tx_Buffer.Elements))
 		{
 			/* Wait until Serial Tx Endpoint Ready for Read/Write */
-			while (!(Endpoint_IsReadWriteAllowed()))
-			{
-				if (USB_DeviceState == DEVICE_STATE_Unattached)
-				  return;
-			}
+			Endpoint_WaitUntilReady();
 				
 			/* Send an empty packet to terminate the transfer */
 			Endpoint_ClearIN();
diff --git a/LUFA/Drivers/USB/Class/Device/CDC.c b/LUFA/Drivers/USB/Class/Device/CDC.c
index 9da0ed1ebf56a60375a979f760c1ad469e5fce71..0d6b378503f0ec6b40c941d22855fa5a0aaddb2c 100644
--- a/LUFA/Drivers/USB/Class/Device/CDC.c
+++ b/LUFA/Drivers/USB/Class/Device/CDC.c
@@ -126,12 +126,7 @@ void CDC_Device_USBTask(USB_ClassInfo_CDC_Device_t* CDCInterfaceInfo)
 	if (!(Endpoint_IsReadWriteAllowed()))
 	{
 		Endpoint_ClearIN();
-
-		while (!(Endpoint_IsReadWriteAllowed()))
-		{
-			if (USB_DeviceState == DEVICE_STATE_Unattached)
-			  return;
-		}
+		Endpoint_WaitUntilReady();
 	}	
 	
 	Endpoint_ClearIN();
@@ -156,12 +151,7 @@ void CDC_Device_SendByte(USB_ClassInfo_CDC_Device_t* const CDCInterfaceInfo, con
 	if (!(Endpoint_IsReadWriteAllowed()))
 	{
 		Endpoint_ClearIN();
-		
-		while (!(Endpoint_IsReadWriteAllowed()))
-		{
-			if (USB_DeviceState == DEVICE_STATE_Unattached)
-			  return;		
-		}
+		Endpoint_WaitUntilReady();
 	}
 
 	Endpoint_Write_Byte(Data);	
diff --git a/LUFA/Drivers/USB/HighLevel/USBInterrupt.c b/LUFA/Drivers/USB/HighLevel/USBInterrupt.c
index a039dffb62d5a3536da895f4541db536e12ac46a..00fe7d1dcb3329bafdd8cd6dd638bec762d3d0c5 100644
--- a/LUFA/Drivers/USB/HighLevel/USBInterrupt.c
+++ b/LUFA/Drivers/USB/HighLevel/USBInterrupt.c
@@ -223,7 +223,7 @@ ISR(USB_GEN_vect, ISR_BLOCK)
 }
 
 #if defined(INTERRUPT_CONTROL_ENDPOINT)
-ISR(USB_COM_vect, ISR_NOBLOCK)
+ISR(USB_COM_vect, ISR_BLOCK)
 {
 	uint8_t PrevSelectedEndpoint = Endpoint_GetCurrentEndpoint();
 
@@ -231,6 +231,6 @@ ISR(USB_COM_vect, ISR_NOBLOCK)
 
 	USB_INT_Clear(USB_INT_ENDPOINT_SETUP);
 	
-	Endpoint_SelectEndpoint(PrevSelectedEndpoint);	
+	Endpoint_SelectEndpoint(PrevSelectedEndpoint);
 }
 #endif