diff --git a/cpu/nrf51/include/cpu_conf.h b/cpu/nrf51/include/cpu_conf.h
index 1f49e12ef41b1de9237754fe34957590b2ba3c0f..17997c2cfd466b79c09f78982722da445d720080 100644
--- a/cpu/nrf51/include/cpu_conf.h
+++ b/cpu/nrf51/include/cpu_conf.h
@@ -44,7 +44,7 @@ extern "C" {
  */
 #define FLASHPAGE_SIZE          (1024U)
 
-#if defined(CPU_MODEL_NRF51X22XXAA)
+#if defined(CPU_MODEL_NRF51X22XXAA) || defined(CPU_MODEL_NRF51X22XXAC)
 #define FLASHPAGE_NUMOF         (256U)
 #elif defined(CPU_MODEL_NRF51X22XXAB)
 #define FLASHPAGE_NUMOF         (128U)