diff --git a/src/core/tcp.c b/src/core/tcp.c
index 12ab32ca..bfeab24c 100644
--- a/src/core/tcp.c
+++ b/src/core/tcp.c
@@ -1126,6 +1126,12 @@ tcp_debug_print_flags(u8_t flags)
   if (flags & TCP_URG) {
     LWIP_DEBUGF(TCP_DEBUG, ("URG "));
   }
+  if (flags & TCP_ECE) {
+    LWIP_DEBUGF(TCP_DEBUG, ("ECE "));
+  }
+  if (flags & TCP_CWR) {
+    LWIP_DEBUGF(TCP_DEBUG, ("CWR "));
+  }
 }
 /*-----------------------------------------------------------------------------------*/
 void
diff --git a/src/include/lwip/tcp.h b/src/include/lwip/tcp.h
index 7969520f..3a988e89 100644
--- a/src/include/lwip/tcp.h
+++ b/src/include/lwip/tcp.h
@@ -121,6 +121,8 @@ void             tcp_rexmit  (struct tcp_pcb *pcb);
 #define TCP_PSH 0x08U
 #define TCP_ACK 0x10U
 #define TCP_URG 0x20U
+#define TCP_ECE 0x40U
+#define TCP_CWR 0x80U
 
 #define TCP_FLAGS 0x3fU