diff --git a/hardware/tools/esp8266/sdk/include/ets_sys.h b/hardware/tools/esp8266/sdk/include/ets_sys.h
index b7b79c341..7908699bb 100644
--- a/hardware/tools/esp8266/sdk/include/ets_sys.h
+++ b/hardware/tools/esp8266/sdk/include/ets_sys.h
@@ -91,10 +91,10 @@ typedef void (*int_handler_t)(void*);
     ETS_INTR_DISABLE(ETS_GPIO_INUM)
 
 
-void *pvPortMalloc(size_t xWantedSize);
-void *pvPortRealloc(void* ptr, size_t xWantedSize);
+void *pvPortMalloc(size_t xWantedSize) __attribute__((malloc, alloc_size(1)));
+void *pvPortRealloc(void* ptr, size_t xWantedSize) __attribute__((alloc_size(2)));
 void pvPortFree(void *ptr);
-void *vPortMalloc(size_t xWantedSize);
+void *vPortMalloc(size_t xWantedSize) __attribute__((malloc, alloc_size(1)));
 void vPortFree(void *ptr);
 void *ets_memcpy(void *dest, const void *src, size_t n);
 void *ets_memset(void *s, int c, size_t n);
diff --git a/hardware/tools/esp8266/sdk/include/osapi.h b/hardware/tools/esp8266/sdk/include/osapi.h
index 6935388c5..11e03803f 100644
--- a/hardware/tools/esp8266/sdk/include/osapi.h
+++ b/hardware/tools/esp8266/sdk/include/osapi.h
@@ -50,7 +50,7 @@
 	os_printf_plus(flash_str, ##__VA_ARGS__);	\
 	} while(0)
 #else
-extern int os_printf_plus(const char * format, ...);
+extern int os_printf_plus(const char * format, ...) __attribute__ ((format (printf, 1, 2)));
 #define os_printf	os_printf_plus
 #endif