diff --git a/cpu/nrf51822/include/cpu-conf.h b/cpu/nrf51822/include/cpu-conf.h
index 51cbd3bbbd..9e48988a5b 100644
--- a/cpu/nrf51822/include/cpu-conf.h
+++ b/cpu/nrf51822/include/cpu-conf.h
@@ -33,7 +33,7 @@ extern "C" {
 #define KERNEL_CONF_STACKSIZE_PRINTF    (512)
 
 #ifndef KERNEL_CONF_STACKSIZE_DEFAULT
-#define KERNEL_CONF_STACKSIZE_DEFAULT   (512)
+#define KERNEL_CONF_STACKSIZE_DEFAULT   (1024)
 #endif
 
 #define KERNEL_CONF_STACKSIZE_IDLE      (256)
diff --git a/tests/pthread_rwlock/Makefile b/tests/pthread_rwlock/Makefile
index 15267df22f..fc571f2336 100644
--- a/tests/pthread_rwlock/Makefile
+++ b/tests/pthread_rwlock/Makefile
@@ -13,6 +13,7 @@ DISABLE_MODULE += auto_init
 CFLAGS += -DNATIVE_AUTO_EXIT
 
 BOARD_INSUFFICIENT_RAM += chronos mbed_lpc1768 msb-430 msb-430h stm32f0discovery \
-                          pca10000 pca10005 yunjia-nrf51822 spark-core nucleo-f334
+                          pca10000 pca10005 yunjia-nrf51822 spark-core nucleo-f334 \
+                          airfy-beacon
 
 include $(RIOTBASE)/Makefile.include