diff --git a/cpu/msp430_common/include/cpu_conf.h b/cpu/msp430_common/include/cpu_conf.h
index 33a12cb858..67b9ec4130 100644
--- a/cpu/msp430_common/include/cpu_conf.h
+++ b/cpu/msp430_common/include/cpu_conf.h
@@ -26,11 +26,11 @@ extern "C" {
  * @name   Configure the internal flash memory
  * @{
  */
-#define FLASHPAGE_SIZE      (512)
+#define FLASHPAGE_SIZE      (512U)
 
 #if defined (CPU_MODEL_MSP430F1611)
 #define CPU_FLASH_BASE      (0x4000)
-#define FLASHPAGE_NUMOF     (96)        /* 48K */
+#define FLASHPAGE_NUMOF     (96U)        /* 48K */
 #elif defined (CPU_MODEL_MSP430F1612)
 #define CPU_FLASH_BASE      (0x2600)    /* first sector is only 256 byte, skip it*/
 #define FLASHPAGE_NUMOF     (109U)      /* 54.5K */
@@ -39,7 +39,7 @@ extern "C" {
 #define FLASHPAGE_NUMOF     (103U)      /* we can currently only access 51.5K */
 #elif defined (CPU_MODEL_CC430F6137)
 #define CPU_FLASH_BASE      (0x8000)
-#define FLASHPAGE_NUMOF     (64)        /* 32K */
+#define FLASHPAGE_NUMOF     (64U)        /* 32K */
 #endif
 /** @} */
 
diff --git a/cpu/msp430_common/periph/flashpage.c b/cpu/msp430_common/periph/flashpage.c
index 2d366c5b34..34151df159 100644
--- a/cpu/msp430_common/periph/flashpage.c
+++ b/cpu/msp430_common/periph/flashpage.c
@@ -26,7 +26,7 @@
 
 void flashpage_write(int page, const void *data)
 {
-    assert(page < FLASHPAGE_NUMOF);
+    assert((unsigned) page < FLASHPAGE_NUMOF);
 
     const uint8_t *src = data;
     uint8_t *dst = (uint8_t *)flashpage_addr(page);