diff --git a/hardware/sam/cores/sam/build_gcc/Makefile b/hardware/sam/cores/sam/build_gcc/Makefile
index f6d40e422..c938789f1 100644
--- a/hardware/sam/cores/sam/build_gcc/Makefile
+++ b/hardware/sam/cores/sam/build_gcc/Makefile
@@ -1,5 +1,5 @@
-# Makefile for compiling libboard
-BOARD = 
+#VARIANTS = sam3s_ek sam3u_ek arduino_due
+VARIANTS = sam3u_ek
 
 SUBMAKE_OPTIONS=--no-builtin-rules --no-builtin-variables
 
@@ -7,18 +7,38 @@ SUBMAKE_OPTIONS=--no-builtin-rules --no-builtin-variables
 # Rules
 #-------------------------------------------------------------------------------
 
-all: sam3s_ek
+all: $(VARIANTS)
 
-.PHONY: sam3s_ek
+.PHONY: sam3s_ek 
 sam3s_ek:
 	@echo --- Making sam3s_ek
 	@$(MAKE) DEBUG=1 $(SUBMAKE_OPTIONS) -f libarduino_sam3s_ek.mk
 #	@$(MAKE) $(SUBMAKE_OPTIONS) -f libarduino_sam3s_ek.mk
 
+.PHONY: sam3u_ek
+sam3u_ek:
+	@echo --- Making sam3u_ek
+	@$(MAKE) DEBUG=1 $(SUBMAKE_OPTIONS) -f libarduino_sam3u_ek.mk
+#	@$(MAKE) $(SUBMAKE_OPTIONS) -f libarduino_sam3u_ek.mk
+
+.PHONY: arduino_due
+arduino_due:
+	@echo --- Making arduino_due
+	@$(MAKE) DEBUG=1 $(SUBMAKE_OPTIONS) -f libarduino_arduino_due.mk
+#	@$(MAKE) $(SUBMAKE_OPTIONS) -f libarduino_arduino_due.mk
+
 .PHONY: clean
 clean:
 	@echo --- Cleaning sam3s_ek
 	@$(MAKE) DEBUG=1 $(SUBMAKE_OPTIONS) -f libarduino_sam3s_ek.mk $@
 #	@$(MAKE) $(SUBMAKE_OPTIONS) -f libarduino_sam3s_ek.mk $@
 
+	@echo --- Cleaning sam3u_ek
+	@$(MAKE) DEBUG=1 $(SUBMAKE_OPTIONS) -f libarduino_sam3u_ek.mk $@
+#	@$(MAKE) $(SUBMAKE_OPTIONS) -f libarduino_sam3u_ek.mk $@
+
+	@echo --- Cleaning arduino_due
+	@$(MAKE) DEBUG=1 $(SUBMAKE_OPTIONS) -f libarduino_arduino_due.mk $@
+#	@$(MAKE) $(SUBMAKE_OPTIONS) -f libarduino_arduino_due.mk $@
+
 
diff --git a/hardware/sam/cores/sam/validation/build_gcc/test.mk b/hardware/sam/cores/sam/validation/build_gcc/test.mk
index 41c384c9a..7d6fed01a 100644
--- a/hardware/sam/cores/sam/validation/build_gcc/test.mk
+++ b/hardware/sam/cores/sam/validation/build_gcc/test.mk
@@ -1,9 +1,10 @@
 # Makefile for compiling libArduino
 .SUFFIXES: .o .a .c .s
 
-CHIP=__SAM3S4C__
-VARIANT=sam3s_ek
-#VARIANT=sam3u_ek
+#CHIP=__SAM3S4C__
+CHIP=__SAM3U4E__
+#VARIANT=sam3s_ek
+VARIANT=sam3u_ek
 #VARIANT=arduino_due
 TOOLCHAIN=gcc
 
diff --git a/hardware/sam/system/libsam/cmsis/sam3u/source/templates/system_sam3u.c b/hardware/sam/system/libsam/cmsis/sam3u/source/templates/system_sam3u.c
index 926f3797f..c107e5ed1 100644
--- a/hardware/sam/system/libsam/cmsis/sam3u/source/templates/system_sam3u.c
+++ b/hardware/sam/system/libsam/cmsis/sam3u/source/templates/system_sam3u.c
@@ -40,7 +40,7 @@ extern "C" {
 #define EFRC_OSC    	( 4000000UL)	/* Embedded fast RC oscillator freq  */
 #define UTMIPLL     	(480000000UL)	/* UTMI PLL frequency 				 */
 #define MAINCK_XTAL_HZ	(12000000UL)	/* External crystal frequency */
-#define MCK_HZ			(48000000UL)	/* Processor frequency */
+#define MCK_HZ		    (96000000UL)   /* Processor frequency */
 
 /* FIXME: should be generated by sock */
 uint32_t SystemCoreClock = EFRC_OSC;
@@ -134,7 +134,7 @@ extern void SystemCoreClockUpdate( void )
 				break;
 			}
 		}
-		if (PMC->PMC_MCKR & PMC_MCKR_CSS_Msk == PMC_MCKR_CSS_PLLA_CLK) {
+		if ((PMC->PMC_MCKR & PMC_MCKR_CSS_Msk) == PMC_MCKR_CSS_PLLA_CLK) {
 			SystemCoreClock *= ((((PMC->CKGR_PLLAR) >> CKGR_PLLAR_MULA_Pos) & 0x7FF) + 1);
 			SystemCoreClock /= ((((PMC->CKGR_PLLAR) >> CKGR_PLLAR_DIVA_Pos) & 0x0FF));
 		}
diff --git a/hardware/sam/system/libsam/include/pmc.h b/hardware/sam/system/libsam/include/pmc.h
index 03f9d9601..e41138a30 100644
--- a/hardware/sam/system/libsam/include/pmc.h
+++ b/hardware/sam/system/libsam/include/pmc.h
@@ -21,7 +21,7 @@
 extern void PMC_EnablePeripheral( uint32_t dwId ) ;
 extern void PMC_DisablePeripheral( uint32_t dwId ) ;
 
-extern uint32_t PMC_IsPeriphEnabled( uint32_t dwId ) ;
+extern uint32_t PMC_IsPeripheralEnabled( uint32_t dwId ) ;
 
 #ifdef __cplusplus
 }
diff --git a/hardware/sam/system/libsam/include/spi.h b/hardware/sam/system/libsam/include/spi.h
index bd44c905e..595708081 100644
--- a/hardware/sam/system/libsam/include/spi.h
+++ b/hardware/sam/system/libsam/include/spi.h
@@ -70,6 +70,7 @@ extern void SPI_Write( Spi* spi, uint32_t dwNpcs, uint16_t wData ) ;
 extern uint32_t SPI_GetStatus( Spi* spi ) ;
 extern uint32_t SPI_IsFinished( Spi* pSpi ) ;
 
+#if (defined _SAM3S_) || (defined _SAM3S8_) || (defined _SAM3N_)
 extern void SPI_PdcEnableTx( Spi* spi ) ;
 extern void SPI_PdcDisableTx( Spi* spi ) ;
 extern void SPI_PdcEnableRx( Spi* spi ) ;
@@ -81,6 +82,7 @@ extern void SPI_PdcSetRx( Spi* spi, void* pvRxBuf, uint32_t dwRxCount, void* pvR
 extern uint32_t SPI_WriteBuffer( Spi* spi, void* pvBuffer, uint32_t dwLength ) ;
 
 extern uint32_t SPI_ReadBuffer( Spi* spi, void* pvBuffer, uint32_t dwLength ) ;
+#endif /* (defined _SAM3S_) || (defined _SAM3S8_) || (defined _SAM3N_) */
 
 #ifdef __cplusplus
 }
diff --git a/hardware/sam/system/libsam/source/spi.c b/hardware/sam/system/libsam/source/spi.c
index d4f708d83..caf58e00d 100644
--- a/hardware/sam/system/libsam/source/spi.c
+++ b/hardware/sam/system/libsam/source/spi.c
@@ -183,6 +183,7 @@ extern uint32_t SPI_IsFinished( Spi* spi )
     return ((spi->SPI_SR & SPI_SR_TXEMPTY) != 0) ;
 }
 
+#if (defined _SAM3S_) || (defined _SAM3S8_) || (defined _SAM3N_)
 /**
  * \brief Enable Spi PDC transmit
  * \param spi  Pointer to an Spi instance.
@@ -322,4 +323,5 @@ extern uint32_t SPI_ReadBuffer( Spi* spi, void *pvBuffer, uint32_t dwLength )
     return 0 ;
 }
 
+#endif /* (defined _SAM3S_) || (defined _SAM3S8_) || (defined _SAM3N_) */