diff --git a/cpu/saml21/include/atmel/saml21e15a.h b/cpu/saml21/include/atmel/saml21e15a.h
index 9b502c16354a561e4f9b777e0e1ae69077ecb9e3..d664a4418206ef687dc333ba55017d5e977f8063 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 488b73331bda984b96968e1157c11c58f7a308f1..2328351e6d16da5007a9130259d2f8cbcc878ee0 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 f1251e0753ba37ee4b883e768c98c1e2a23fc488..4b5bd13750e7c306d98ba2bce285c09d7da52cf3 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 a6dcda6888d657076053b08e11a8b133d5ec75e6..f18470f7366e265b1502a3e296dd2822ac0e7e52 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 1cb991433be49f53fb7cadd53c9e7aa26d9af41e..559c532f577f1d59f6f22f76385419593159da92 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 884e97c5ce1b2b65f41fb8ae3718606b72f30b80..72f77ba6bf6716b661f1fa89724e02544e4df130 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 2f036b5e98debb60f7de2c3c824ed654206e8e0b..36ff67dab064181e0f453183f01c12d295a2a23b 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 c53599cd6f456d4918a8fbd4333199ec2bdf2c7f..8f5688b80b3af2fa2762f99b48a2ccf854a2c87d 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 fc8eb48b72ca4367eb92e087804dab3b50fc3808..b989e4043397f35cfe9d1618c74bbd70ba1418af 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 */