diff --git a/cpu/stm32f4/periph/hwrng.c b/cpu/stm32f4/periph/hwrng.c
index f5acc72823..e54deeedd7 100644
--- a/cpu/stm32f4/periph/hwrng.c
+++ b/cpu/stm32f4/periph/hwrng.c
@@ -56,4 +56,4 @@ void hwrng_read(uint8_t *buf, unsigned int num)
     periph_clk_dis(AHB2, RCC_AHB2ENR_RNGEN);
 }
 
-#endif /* CPUID_LEN */
+#endif /* RNG */