diff --git a/libraries/Portenta_SDRAM/src/SDRAM.h b/libraries/Portenta_SDRAM/src/SDRAM.h
index d5e8ef36b..0d8808f2d 100644
--- a/libraries/Portenta_SDRAM/src/SDRAM.h
+++ b/libraries/Portenta_SDRAM/src/SDRAM.h
@@ -1,3 +1,6 @@
+#ifndef __SDRAM_H
+#define __SDRAM_H
+
 #include "ea_malloc.h"
 
 #ifdef __cplusplus
@@ -35,4 +38,5 @@ class SDRAMClass {
 
 extern SDRAMClass SDRAM;
 
-#endif
\ No newline at end of file
+#endif
+#endif // __SDRAM_H
diff --git a/libraries/Portenta_SDRAM/src/ram_internal.h b/libraries/Portenta_SDRAM/src/ram_internal.h
index 497ffb020..1d6ff0721 100644
--- a/libraries/Portenta_SDRAM/src/ram_internal.h
+++ b/libraries/Portenta_SDRAM/src/ram_internal.h
@@ -1,3 +1,6 @@
+#ifndef __RAM_INTERNAL_H
+#define __RAM_INTERNAL_H
+
 bool sdram_init(void);
 
 #define MPU_REGION_SDRAM1	(MPU_REGION_NUMBER4)
@@ -56,3 +59,5 @@ bool sdram_init(void);
                                  | (size)                        << MPU_RASR_SIZE_Pos \
                                  | MPU_REGION_ENABLE             << MPU_RASR_ENABLE_Pos \
                                )
+
+#endif // __RAM_INTERNAL_H