diff --git a/lwip/src/include/lwipopts.h b/lwip/src/include/lwipopts.h
index bb3e4bf4..9152689e 100644
--- a/lwip/src/include/lwipopts.h
+++ b/lwip/src/include/lwipopts.h
@@ -240,7 +240,7 @@
 #define PBUF_DEBUG		LWIP_DBG_OFF
 
 // we need this feature to avoid memcpy operation between user- and kernel space
-//#define LWIP_TCPIP_CORE_LOCKING		1
+#define LWIP_TCPIP_CORE_LOCKING		1
 
 //#define LWIP_TCPIP_THREAD_ALIVE()	kputs("TCPIP thread is alive!\n")
 #endif