diff --git a/Bootloaders/TeensyHID/Descriptors.c b/Bootloaders/TeensyHID/Descriptors.c
index 2832ec3935..4142f12474 100644
--- a/Bootloaders/TeensyHID/Descriptors.c
+++ b/Bootloaders/TeensyHID/Descriptors.c
@@ -157,26 +157,29 @@ uint16_t CALLBACK_USB_GetDescriptor(const uint16_t wValue, const uint8_t wIndex,
 	void*    Address = NULL;
 	uint16_t Size    = NO_DESCRIPTOR;
 
-	switch (DescriptorType)
+	/* If/Else If chain compiles slightly smaller than a switch case */
+
+	if (DescriptorType == DTYPE_Device)
+	{
+		Address = (void*)&DeviceDescriptor;
+		Size    = sizeof(USB_Descriptor_Device_t);	
+	}
+	else if (DescriptorType == DTYPE_Device)
+	{
+		Address = (void*)&ConfigurationDescriptor;
+		Size    = sizeof(USB_Descriptor_Configuration_t);	
+	}
+	else if (DescriptorType == DTYPE_HID)
+	{
+		Address = (void*)&ConfigurationDescriptor.HID_VendorHID;
+		Size    = sizeof(USB_Descriptor_HID_t);
+	}
+	else
 	{
-		case DTYPE_Device:
-			Address = (void*)&DeviceDescriptor;
-			Size    = sizeof(USB_Descriptor_Device_t);
-			break;
-		case DTYPE_Configuration:
-			Address = (void*)&ConfigurationDescriptor;
-			Size    = sizeof(USB_Descriptor_Configuration_t);
-			break;
-		case DTYPE_HID:
-			Address = (void*)&ConfigurationDescriptor.HID_VendorHID;
-			Size    = sizeof(USB_Descriptor_HID_t);
-			break;
-		case DTYPE_Report:
-			Address = (void*)&HIDReport;
-			Size    = sizeof(HIDReport);
-			break;
+		Address = (void*)&HIDReport;
+		Size    = sizeof(HIDReport);
 	}
-	
+
 	*DescriptorAddress = Address;
 	return Size;
 }
diff --git a/LUFA/Drivers/USB/LowLevel/DevChapter9.c b/LUFA/Drivers/USB/LowLevel/DevChapter9.c
index 17a5fd4714..b7f811b5eb 100644
--- a/LUFA/Drivers/USB/LowLevel/DevChapter9.c
+++ b/LUFA/Drivers/USB/LowLevel/DevChapter9.c
@@ -136,8 +136,7 @@ static void USB_Device_SetAddress(void)
 		  return;
 	}
 
-	if (DeviceAddress)
-	  USB_DeviceState = DEVICE_STATE_Addressed;
+	USB_DeviceState = (DeviceAddress) ? DEVICE_STATE_Addressed : DEVICE_STATE_Default;
 
 	UDADDR = ((1 << ADDEN) | DeviceAddress);
 
@@ -146,12 +145,21 @@ static void USB_Device_SetAddress(void)
 
 static void USB_Device_SetConfiguration(void)
 {
+	if (USB_DeviceState != DEVICE_STATE_Addressed)
+	  return;
+	
 #if defined(FIXED_NUM_CONFIGURATIONS)
 	if ((uint8_t)USB_ControlRequest.wValue > FIXED_NUM_CONFIGURATIONS)
 	  return;
 #else
-	#if !defined(USE_FLASH_DESCRIPTORS) && !defined(USE_EEPROM_DESCRIPTORS) && !defined(USE_RAM_DESCRIPTORS)
-	uint8_t MemoryAddressSpace;
+	#if defined(USE_FLASH_DESCRIPTORS)
+		#define MemoryAddressSpace  MEMSPACE_FLASH
+	#elif defined(USE_EEPROM_DESCRIPTORS)
+		#define MemoryAddressSpace  MEMSPACE_EEPROM
+	#elif defined(USE_SRAM_DESCRIPTORS)
+		#define MemoryAddressSpace  MEMSPACE_SRAM
+	#else
+		uint8_t MemoryAddressSpace;
 	#endif
 	
 	USB_Descriptor_Device_t* DevDescriptorPtr;
@@ -165,16 +173,6 @@ static void USB_Device_SetConfiguration(void)
 		return;
 	}
 	
-	#if defined(USE_RAM_DESCRIPTORS)
-	if ((uint8_t)USB_ControlRequest.wValue > DevDescriptorPtr->NumberOfConfigurations)
-	  return;
-	#elif defined (USE_EEPROM_DESCRIPTORS)
-	if ((uint8_t)USB_ControlRequest.wValue > eeprom_read_byte(&DevDescriptorPtr->NumberOfConfigurations))
-	  return;
-	#elif defined (USE_FLASH_DESCRIPTORS)
-	if ((uint8_t)USB_ControlRequest.wValue > pgm_read_byte(&DevDescriptorPtr->NumberOfConfigurations))
-	  return;
-	#else
 	if (MemoryAddressSpace == MEMSPACE_FLASH)
 	{
 		if (((uint8_t)USB_ControlRequest.wValue > pgm_read_byte(&DevDescriptorPtr->NumberOfConfigurations)))
@@ -190,7 +188,6 @@ static void USB_Device_SetConfiguration(void)
 		if ((uint8_t)USB_ControlRequest.wValue > DevDescriptorPtr->NumberOfConfigurations)
 		  return;
 	}
-	#endif
 #endif
 	
 	Endpoint_ClearSETUP();
@@ -234,17 +231,20 @@ static void USB_Device_GetInternalSerialDescriptor(void)
 	
 	uint8_t SigReadAddress = 0x0E;
 
-	for (uint8_t SerialCharNum = 0; SerialCharNum < 20; SerialCharNum++)
+	ATOMIC_BLOCK(ATOMIC_RESTORESTATE)
 	{
-		uint8_t SerialByte = boot_signature_byte_get(SigReadAddress);
-		
-		if (SerialCharNum & 0x01)
+		for (uint8_t SerialCharNum = 0; SerialCharNum < 20; SerialCharNum++)
 		{
-			SerialByte >>= 4;
-			SigReadAddress++;
+			uint8_t SerialByte = boot_signature_byte_get(SigReadAddress);
+			
+			if (SerialCharNum & 0x01)
+			{
+				SerialByte >>= 4;
+				SigReadAddress++;
+			}
+			
+			SignatureDescriptor.UnicodeString[SerialCharNum] = USB_Device_NibbleToASCII(SerialByte);
 		}
-		
-		SignatureDescriptor.UnicodeString[SerialCharNum] = USB_Device_NibbleToASCII(SerialByte);
 	}
 	
 	Endpoint_ClearSETUP();
diff --git a/LUFA/Drivers/USB/LowLevel/DevChapter9.h b/LUFA/Drivers/USB/LowLevel/DevChapter9.h
index d591327390..868c3fab21 100644
--- a/LUFA/Drivers/USB/LowLevel/DevChapter9.h
+++ b/LUFA/Drivers/USB/LowLevel/DevChapter9.h
@@ -46,6 +46,7 @@
 		#include <avr/pgmspace.h>
 		#include <avr/eeprom.h>
 		#include <avr/boot.h>
+		#include <util/atomic.h>
 		
 		#include "../HighLevel/StdDescriptors.h"
 		#include "../HighLevel/Events.h"
diff --git a/LUFA/ManPages/ChangeLog.txt b/LUFA/ManPages/ChangeLog.txt
index 8d5a7ab6a4..c38f9e73e6 100644
--- a/LUFA/ManPages/ChangeLog.txt
+++ b/LUFA/ManPages/ChangeLog.txt
@@ -52,6 +52,12 @@
   *  - Fixed Set/Clear Feature requests directed to a non-configured endpoint not returning a stall to the host
   *  - Fixed HID Device Class Driver not allocating a temporary buffer when the host requests a report via the control endpoint and the
   *    user has set the PrevReportINBuffer driver configuration element to NULL (thanks to Lars Noschinski)
+  *  - Fixed device state not being reset to DEVICE_STATE_Default if the host sets a 0x00 device address
+  *  - Fixed device not stalling configuration requests before the device's address has been set
+  *  - Fixed possibility of internal signature retrieval being corrupted if an interrupt occurs during a signature byte
+  *    read (thanks to Andrei Krainev)
+  *  - Fixed device state not being reset back to the default state if the host sets the address to 0
+  *  - Fixed Set Configuration requests not being stalled until the host has set the device's address
   *
   *  \section Sec_ChangeLog100219 Version 100219
   *
diff --git a/Projects/AVRISP-MKII/AVRISP.txt b/Projects/AVRISP-MKII/AVRISP.txt
index fddae6d2bb..6109031106 100644
--- a/Projects/AVRISP-MKII/AVRISP.txt
+++ b/Projects/AVRISP-MKII/AVRISP.txt
@@ -56,14 +56,15 @@
  *  Note that this design currently has the following limitations:
  *    - Minimum ISP target clock speed of 500KHz due to hardware SPI module prescaler limitations
  *    - No reversed/shorted target connector detection and notification
+ *    - Very slow TPI and PDI programming when in software emulated USART mode
  *
  *  On AVR models with an ADC converter, AVCC should be tied to 5V (e.g. VBUS) and the VTARGET_ADC_CHANNEL token should be
  *  set to an appropriate ADC channel number in the project makefile for VTARGET detection to operate correctly. On models
  *  without an ADC converter, VTARGET will report a fixed 5V level at all times.
  *
  *  When compiled for the XPLAIN board target, this will automatically configure itself for the correct connections to the
- *  XPLAIN's XMEGA AVR, and will enable PDI/TPI only programming support (since ISP mode is not needed). Note that the
- *  first revision XPLAIN board lacks a bootloader on the AT90USB1287, and thus for this firmware to be loaded, an external
+ *  XPLAIN's XMEGA AVR, and will enable hardware PDI/TPI only programming support (since ISP mode is not needed). Note that
+ *  the first revision XPLAIN board lacks a bootloader on the AT90USB1287, and thus for this firmware to be loaded, an external
  *  programmer will be required.
  *
  *  While this application can be compiled for USB AVRs with as little as 8KB of FLASH, for full functionality 16KB or more