diff --git a/src/api/api_lib.c b/src/api/api_lib.c
index 9b8236c9..cd9b81ff 100644
--- a/src/api/api_lib.c
+++ b/src/api/api_lib.c
@@ -559,7 +559,7 @@ netconn_recv_data(struct netconn *conn, void **new_buf, u8_t apiflags)
 }
 
 static err_t
-netconn_tcp_recvd_msg(struct netconn *conn, u16_t len, struct api_msg* msg)
+netconn_tcp_recvd_msg(struct netconn *conn, u32_t len, struct api_msg* msg)
 {
   LWIP_ERROR("netconn_recv_tcp_pbuf: invalid conn", (conn != NULL) &&
              NETCONNTYPE_GROUP(netconn_type(conn)) == NETCONN_TCP, return ERR_ARG;);
@@ -571,7 +571,7 @@ netconn_tcp_recvd_msg(struct netconn *conn, u16_t len, struct api_msg* msg)
 }
 
 err_t
-netconn_tcp_recvd(struct netconn *conn, u16_t len)
+netconn_tcp_recvd(struct netconn *conn, u32_t len)
 {
   err_t err;
   API_MSG_VAR_DECLARE(msg);
diff --git a/src/include/lwip/api.h b/src/include/lwip/api.h
index 333db681..4fb8038c 100644
--- a/src/include/lwip/api.h
+++ b/src/include/lwip/api.h
@@ -320,7 +320,7 @@ err_t   netconn_recv_udp_raw_netbuf(struct netconn *conn, struct netbuf **new_bu
 err_t   netconn_recv_udp_raw_netbuf_flags(struct netconn *conn, struct netbuf **new_buf, u8_t apiflags);
 err_t   netconn_recv_tcp_pbuf(struct netconn *conn, struct pbuf **new_buf);
 err_t   netconn_recv_tcp_pbuf_flags(struct netconn *conn, struct pbuf **new_buf, u8_t apiflags);
-err_t   netconn_tcp_recvd(struct netconn *conn, u16_t len);
+err_t   netconn_tcp_recvd(struct netconn *conn, u32_t len);
 err_t   netconn_sendto(struct netconn *conn, struct netbuf *buf,
                              const ip_addr_t *addr, u16_t port);
 err_t   netconn_send(struct netconn *conn, struct netbuf *buf);