diff -Naurp binutils/size.c binutils/size.c
--- binutils/size.c	2011-09-05 15:43:49.000000000 +0300
+++ binutils/size.c	2011-09-05 15:44:57.000000000 +0300
@@ -121,6 +121,7 @@ avr_device_t avr[] =
 {
 	{"atxmega256a3",  AVR264K, AVR16K, AVR4K},
 	{"atxmega256a3b", AVR264K, AVR16K, AVR4K},
+	{"atxmega256a3bu",AVR264K, AVR16K, AVR4K},
 	{"atxmega256d3",  AVR264K, AVR16K, AVR4K},
 
 	{"atmega2560",    AVR256K, AVR8K,  AVR4K},
diff -Naurp gas/config/tc-avr.c gas/config/tc-avr.c
--- gas/config/tc-avr.c	2011-09-05 15:43:49.000000000 +0300
+++ gas/config/tc-avr.c	2011-09-05 15:44:57.000000000 +0300
@@ -263,6 +263,7 @@ static struct mcu_type_s mcu_types[] =
   {"atxmega192d3", AVR_ISA_XMEGA, bfd_mach_avrxmega6},
   {"atxmega256a3", AVR_ISA_XMEGA, bfd_mach_avrxmega6},
   {"atxmega256a3b",AVR_ISA_XMEGA, bfd_mach_avrxmega6},
+  {"atxmega256a3bu",AVR_ISA_XMEGA,bfd_mach_avrxmega6},
   {"atxmega256d3", AVR_ISA_XMEGA, bfd_mach_avrxmega6},
   {"atxmega128a1", AVR_ISA_XMEGA, bfd_mach_avrxmega7},
   {"atxmega128a1u",AVR_ISA_XMEGA, bfd_mach_avrxmega7},
diff -Naurp gas/doc/c-avr.texi gas/doc/c-avr.texi
--- gas/doc/c-avr.texi	2011-09-05 15:43:49.000000000 +0300
+++ gas/doc/c-avr.texi	2011-09-05 15:44:57.000000000 +0300
@@ -103,7 +103,7 @@ atxmega64a1u).
 Instruction set avrxmega6 is for the XMEGA AVR core with up to 256K program
 memory space and less than 64K data space (MCU types: atxmega128a3,
 atxmega128d3, atxmega192a3, atxmega128b1, atxmega192d3, atxmega256a3, 
-atxmega256a3b, atxmega192d3).
+atxmega256a3b, atxmega256a3bu, atxmega192d3).
 
 Instruction set avrxmega7 is for the XMEGA AVR core with up to 256K program
 memory space and greater than 64K data space (MCU types: atxmega128a1,