diff --git a/cpu/saml21/include/atmel/saml21e15a.h b/cpu/saml21/include/atmel/saml21e15a.h
index 9b502c163..d664a4418 100644
--- a/cpu/saml21/include/atmel/saml21e15a.h
+++ b/cpu/saml21/include/atmel/saml21e15a.h
@@ -231,7 +231,9 @@ void PICOP_Handler               ( void );
  * \brief Configuration of the Cortex-M0+ Processor and Core Peripherals
  */
 
-#define LITTLE_ENDIAN          1
+#ifndef LITTLE_ENDIAN
+#   define LITTLE_ENDIAN       1
+#endif
 #define __CM0PLUS_REV          1         /*!< Core revision r0p1 */
 #define __MPU_PRESENT          0         /*!< MPU present or not */
 #define __NVIC_PRIO_BITS       2         /*!< Number of bits used for Priority Levels */
diff --git a/cpu/saml21/include/atmel/saml21e16a.h b/cpu/saml21/include/atmel/saml21e16a.h
index 488b73331..2328351e6 100644
--- a/cpu/saml21/include/atmel/saml21e16a.h
+++ b/cpu/saml21/include/atmel/saml21e16a.h
@@ -231,7 +231,9 @@ void PICOP_Handler               ( void );
  * \brief Configuration of the Cortex-M0+ Processor and Core Peripherals
  */
 
-#define LITTLE_ENDIAN          1
+#ifndef LITTLE_ENDIAN
+#   define LITTLE_ENDIAN       1
+#endif
 #define __CM0PLUS_REV          1         /*!< Core revision r0p1 */
 #define __MPU_PRESENT          0         /*!< MPU present or not */
 #define __NVIC_PRIO_BITS       2         /*!< Number of bits used for Priority Levels */
diff --git a/cpu/saml21/include/atmel/saml21e17a.h b/cpu/saml21/include/atmel/saml21e17a.h
index f1251e075..4b5bd1375 100644
--- a/cpu/saml21/include/atmel/saml21e17a.h
+++ b/cpu/saml21/include/atmel/saml21e17a.h
@@ -231,7 +231,9 @@ void PICOP_Handler               ( void );
  * \brief Configuration of the Cortex-M0+ Processor and Core Peripherals
  */
 
-#define LITTLE_ENDIAN          1
+#ifndef LITTLE_ENDIAN
+#   define LITTLE_ENDIAN       1
+#endif
 #define __CM0PLUS_REV          1         /*!< Core revision r0p1 */
 #define __MPU_PRESENT          0         /*!< MPU present or not */
 #define __NVIC_PRIO_BITS       2         /*!< Number of bits used for Priority Levels */
diff --git a/cpu/saml21/include/atmel/saml21g16a.h b/cpu/saml21/include/atmel/saml21g16a.h
index a6dcda688..f18470f73 100644
--- a/cpu/saml21/include/atmel/saml21g16a.h
+++ b/cpu/saml21/include/atmel/saml21g16a.h
@@ -235,7 +235,9 @@ void PICOP_Handler               ( void );
  * \brief Configuration of the Cortex-M0+ Processor and Core Peripherals
  */
 
-#define LITTLE_ENDIAN          1
+#ifndef LITTLE_ENDIAN
+#   define LITTLE_ENDIAN       1
+#endif
 #define __CM0PLUS_REV          1         /*!< Core revision r0p1 */
 #define __MPU_PRESENT          0         /*!< MPU present or not */
 #define __NVIC_PRIO_BITS       2         /*!< Number of bits used for Priority Levels */
diff --git a/cpu/saml21/include/atmel/saml21g17a.h b/cpu/saml21/include/atmel/saml21g17a.h
index 1cb991433..559c532f5 100644
--- a/cpu/saml21/include/atmel/saml21g17a.h
+++ b/cpu/saml21/include/atmel/saml21g17a.h
@@ -235,7 +235,9 @@ void PICOP_Handler               ( void );
  * \brief Configuration of the Cortex-M0+ Processor and Core Peripherals
  */
 
-#define LITTLE_ENDIAN          1
+#ifndef LITTLE_ENDIAN
+#   define LITTLE_ENDIAN       1
+#endif
 #define __CM0PLUS_REV          1         /*!< Core revision r0p1 */
 #define __MPU_PRESENT          0         /*!< MPU present or not */
 #define __NVIC_PRIO_BITS       2         /*!< Number of bits used for Priority Levels */
diff --git a/cpu/saml21/include/atmel/saml21g18a.h b/cpu/saml21/include/atmel/saml21g18a.h
index 884e97c5c..72f77ba6b 100644
--- a/cpu/saml21/include/atmel/saml21g18a.h
+++ b/cpu/saml21/include/atmel/saml21g18a.h
@@ -235,7 +235,9 @@ void PICOP_Handler               ( void );
  * \brief Configuration of the Cortex-M0+ Processor and Core Peripherals
  */
 
-#define LITTLE_ENDIAN          1
+#ifndef LITTLE_ENDIAN
+#   define LITTLE_ENDIAN       1
+#endif
 #define __CM0PLUS_REV          1         /*!< Core revision r0p1 */
 #define __MPU_PRESENT          0         /*!< MPU present or not */
 #define __NVIC_PRIO_BITS       2         /*!< Number of bits used for Priority Levels */
diff --git a/cpu/saml21/include/atmel/saml21j16a.h b/cpu/saml21/include/atmel/saml21j16a.h
index 2f036b5e9..36ff67dab 100644
--- a/cpu/saml21/include/atmel/saml21j16a.h
+++ b/cpu/saml21/include/atmel/saml21j16a.h
@@ -239,7 +239,9 @@ void PICOP_Handler               ( void );
  * \brief Configuration of the Cortex-M0+ Processor and Core Peripherals
  */
 
-#define LITTLE_ENDIAN          1
+#ifndef LITTLE_ENDIAN
+#   define LITTLE_ENDIAN       1
+#endif
 #define __CM0PLUS_REV          1         /*!< Core revision r0p1 */
 #define __MPU_PRESENT          0         /*!< MPU present or not */
 #define __NVIC_PRIO_BITS       2         /*!< Number of bits used for Priority Levels */
diff --git a/cpu/saml21/include/atmel/saml21j17a.h b/cpu/saml21/include/atmel/saml21j17a.h
index c53599cd6..8f5688b80 100644
--- a/cpu/saml21/include/atmel/saml21j17a.h
+++ b/cpu/saml21/include/atmel/saml21j17a.h
@@ -239,7 +239,9 @@ void PICOP_Handler               ( void );
  * \brief Configuration of the Cortex-M0+ Processor and Core Peripherals
  */
 
-#define LITTLE_ENDIAN          1
+#ifndef LITTLE_ENDIAN
+#   define LITTLE_ENDIAN       1
+#endif
 #define __CM0PLUS_REV          1         /*!< Core revision r0p1 */
 #define __MPU_PRESENT          0         /*!< MPU present or not */
 #define __NVIC_PRIO_BITS       2         /*!< Number of bits used for Priority Levels */
diff --git a/cpu/saml21/include/atmel/saml21j18a.h b/cpu/saml21/include/atmel/saml21j18a.h
index fc8eb48b7..b989e4043 100644
--- a/cpu/saml21/include/atmel/saml21j18a.h
+++ b/cpu/saml21/include/atmel/saml21j18a.h
@@ -239,7 +239,9 @@ void PICOP_Handler               ( void );
  * \brief Configuration of the Cortex-M0+ Processor and Core Peripherals
  */
 
-#define LITTLE_ENDIAN          1
+#ifndef LITTLE_ENDIAN
+#   define LITTLE_ENDIAN       1
+#endif
 #define __CM0PLUS_REV          1         /*!< Core revision r0p1 */
 #define __MPU_PRESENT          0         /*!< MPU present or not */
 #define __NVIC_PRIO_BITS       2         /*!< Number of bits used for Priority Levels */