diff --git a/examples/device/cdc_msc_freertos/src/FreeRTOSConfig.h b/examples/device/cdc_msc_freertos/src/FreeRTOSConfig.h
index ac274b5f7..0945baf1f 100644
--- a/examples/device/cdc_msc_freertos/src/FreeRTOSConfig.h
+++ b/examples/device/cdc_msc_freertos/src/FreeRTOSConfig.h
@@ -58,8 +58,11 @@
 #elif CFG_TUSB_MCU == OPT_MCU_NRF5X
   #include "nrf.h"
 
-#elif CFG_TUSB_MCU == OPT_MCU_SAMD21 || CFG_TUSB_MCU == OPT_MCU_SAMD51 || \
-      CFG_TUSB_MCU == OPT_MCU_SAMG
+#elif CFG_TUSB_MCU == OPT_MCU_SAMD21 || CFG_TUSB_MCU == OPT_MCU_SAMD51
+  #include "sam.h"
+
+#elif CFG_TUSB_MCU == OPT_MCU_SAMG
+  #undef LITTLE_ENDIAN // hack to suppress "LITTLE_ENDIAN" redefined
   #include "sam.h"
 
 #elif CFG_TUSB_MCU == OPT_MCU_STM32F0
diff --git a/hw/bsp/board.h b/hw/bsp/board.h
index 4c5716d96..a8f973a7f 100644
--- a/hw/bsp/board.h
+++ b/hw/bsp/board.h
@@ -39,7 +39,6 @@
 #include <stdbool.h>
 
 #include "ansi_escape.h"
-
 #include "tusb.h"
 
 #define CFG_BOARD_UART_BAUDRATE    115200
@@ -68,18 +67,21 @@ int board_uart_write(void const * buf, int len);
 #if CFG_TUSB_OS == OPT_OS_NONE
   // Get current milliseconds, must be implemented when no RTOS is used
   uint32_t board_millis(void);
+
 #elif CFG_TUSB_OS == OPT_OS_FREERTOS
   static inline uint32_t board_millis(void)
   {
     return ( ( ((uint64_t) xTaskGetTickCount()) * 1000) / configTICK_RATE_HZ );
   }
+
 #elif CFG_TUSB_OS == OPT_OS_MYNEWT
   static inline uint32_t board_millis(void)
   {
     return os_time_ticks_to_ms32( os_time_get() );
   }
+
 #else
-  #error "Need to implement board_millis() for this OS"
+  #error "board_millis() is not implemented for this OS"
 #endif
 
 //--------------------------------------------------------------------+
@@ -95,6 +97,7 @@ static inline void board_led_off(void)
   board_led_write(false);
 }
 
+// TODO remove
 static inline void board_delay(uint32_t ms)
 {
   uint32_t start_ms = board_millis();
diff --git a/hw/bsp/lpcxpresso55s69/board.mk b/hw/bsp/lpcxpresso55s69/board.mk
index 722f6c6c5..4cb2d00e5 100644
--- a/hw/bsp/lpcxpresso55s69/board.mk
+++ b/hw/bsp/lpcxpresso55s69/board.mk
@@ -39,7 +39,7 @@ VENDOR = nxp
 CHIP_FAMILY = lpc_ip3511
 
 # For freeRTOS port source
-FREERTOS_PORT = ARM_CM33/non_secure
+FREERTOS_PORT = ARM_CM33_NTZ/non_secure
 
 # For flash-jlink target
 JLINK_DEVICE = LPC55S69
diff --git a/hw/bsp/samg55xplained/board.mk b/hw/bsp/samg55xplained/board.mk
index 1fd137465..e0c24ed9c 100644
--- a/hw/bsp/samg55xplained/board.mk
+++ b/hw/bsp/samg55xplained/board.mk
@@ -9,7 +9,8 @@ CFLAGS += \
   -D__SAMG55J19__ \
   -DCFG_TUSB_MCU=OPT_MCU_SAMG
 
-#CFLAGS += -Wno-error=undef
+# suppress following warnings from mcu driver
+CFLAGS += -Wno-error=undef
 
 ASF_DIR = hw/mcu/microchip/samg55