diff --git a/lib/libwebsockets.h b/lib/libwebsockets.h
index ec1757150..851c38d70 100644
--- a/lib/libwebsockets.h
+++ b/lib/libwebsockets.h
@@ -38,12 +38,15 @@ namespace {
 using namespace mbed::Sockets::v0;
 
 struct libwebsocket;
+struct libwebsocket_context;
 
 class lws_conn {
 	public:
 	lws_conn():
 		ts(NULL),
-		wsi(NULL)
+		wsi(NULL),
+		writeable(1),
+		awaiting_on_writeable(0)
 	{
 	}
 
@@ -54,14 +57,16 @@ public:
 	void onError(Socket *s, socket_error_t err);
 	void onDisconnect(TCPStream *s);
 	void onSent(Socket *s, uint16_t len);
+	void serialized_writeable(struct libwebsocket *wsi);
 
 public:
 	TCPStream *ts;
-	Socket *s_HACK;
 	
 public:
 	struct libwebsocket *wsi;
 	char buffer[BUFFER_SIZE];
+	char writeable;
+	char awaiting_on_writeable;
 };
 
 class lws_conn_listener : lws_conn {
@@ -137,7 +142,7 @@ extern "C" {
 #include <poll.h>
 #include <netdb.h>
 #else
-#define getdtablesize() (10)
+#define getdtablesize() (20)
 #endif
 
 #if defined(__GNUC__)
diff --git a/lib/lws-plat-mbed3.c b/lib/lws-plat-mbed3.c
index 264ee9c55..d11bfeed4 100644
--- a/lib/lws-plat-mbed3.c
+++ b/lib/lws-plat-mbed3.c
@@ -91,76 +91,6 @@ LWS_VISIBLE void lwsl_emit_syslog(int level, const char *line)
 	printf("%d: %s", level, line);
 }
 
-LWS_VISIBLE int
-lws_plat_service(struct libwebsocket_context *context, int timeout_ms)
-{
-	(void)context;
-	(void)timeout_ms;
-#if 0
-	int n;
-	int m;
-	char buf;
-#ifdef LWS_OPENSSL_SUPPORT
-	struct libwebsocket *wsi, *wsi_next;
-#endif
-
-	/* stay dead once we are dead */
-
-	if (!context)
-		return 1;
-
-	lws_libev_run(context);
-
-	context->service_tid = context->protocols[0].callback(context, NULL,
-				     LWS_CALLBACK_GET_THREAD_ID, NULL, NULL, 0);
-
-#ifdef LWS_OPENSSL_SUPPORT
-	/* if we know we have non-network pending data, do not wait in poll */
-	if (lws_ssl_anybody_has_buffered_read(context))
-		timeout_ms = 0;
-#endif
-	n = poll(context->fds, context->fds_count, timeout_ms);
-	context->service_tid = 0;
-
-#ifdef LWS_OPENSSL_SUPPORT
-	if (!lws_ssl_anybody_has_buffered_read(context) && n == 0) {
-#else
-	if (n == 0) /* poll timeout */ {
-#endif
-		libwebsocket_service_fd(context, NULL);
-		return 0;
-	}
-
-	if (n < 0) {
-		if (LWS_ERRNO != LWS_EINTR)
-			return -1;
-		return 0;
-	}
-
-	/* any socket with events to service? */
-
-	for (n = 0; n < context->fds_count; n++) {
-
-		if (!context->fds[n].revents)
-			continue;
-
-		if (context->fds[n].fd == context->dummy_pipe_fds[0]) {
-			if (read(context->fds[n].fd, &buf, 1) != 1)
-				lwsl_err("Cannot read from dummy pipe.");
-			continue;
-		}
-
-		m = libwebsocket_service_fd(context, &context->fds[n]);
-		if (m < 0)
-			return -1;
-		/* if something closed, retry this slot */
-		if (m)
-			n--;
-	}
-#endif
-	return 0;
-}
-
 LWS_VISIBLE int
 lws_plat_set_socket_options(struct libwebsocket_context *context, lws_sockfd_type fd)
 {
@@ -215,17 +145,6 @@ lws_plat_service_periodic(struct libwebsocket_context *context)
 	(void)context;
 }
 
-LWS_VISIBLE int
-lws_plat_change_pollfd(struct libwebsocket_context *context,
-		      struct libwebsocket *wsi, struct libwebsocket_pollfd *pfd)
-{
-	(void)context;
-	(void)wsi;
-	(void)pfd;
-	
-	return 0;
-}
-
 LWS_VISIBLE int
 lws_plat_open_file(const char* filename, unsigned long* filelen)
 {
diff --git a/lib/lws-plat-mbed3.cpp b/lib/lws-plat-mbed3.cpp
index 1c9a049ae..ca0a1a339 100644
--- a/lib/lws-plat-mbed3.cpp
+++ b/lib/lws-plat-mbed3.cpp
@@ -21,11 +21,28 @@ extern "C" void mbed3_delete_tcp_stream_socket(void *sock)
 	delete conn;
 }
 
+void lws_conn::serialized_writeable(struct libwebsocket *_wsi)
+{
+	struct libwebsocket *wsi = (struct libwebsocket *)_wsi;
+	struct libwebsocket_pollfd pollfd;
+	lws_conn *conn = (lws_conn *)wsi->sock;
+	
+	conn->awaiting_on_writeable = 0;
+
+	pollfd.fd = wsi->sock;
+	pollfd.events = POLLOUT;
+	pollfd.revents = POLLOUT;
+
+	lwsl_debug("%s: wsi %p\r\n", __func__, (void *)wsi);
+
+	libwebsocket_service_fd(wsi->protocol->owning_server, &pollfd);
+}
+
 extern "C" void mbed3_tcp_stream_bind(void *sock, int port, struct libwebsocket *wsi)
 {
 	lws_conn_listener *srv = (lws_conn_listener *)sock;
 	
-	lwsl_info("%s\r\n", __func__);
+	lwsl_debug("%s\r\n", __func__);
 	/* associate us with the listening wsi */
 	((lws_conn *)srv)->set_wsi(wsi);
 
@@ -37,22 +54,44 @@ extern "C" void mbed3_tcp_stream_accept(void *sock, struct libwebsocket *wsi)
 {
 	lws_conn *conn = (lws_conn *)sock;
 
-	lwsl_info("%s\r\n", __func__);
+	lwsl_debug("%s\r\n", __func__);
 	conn->set_wsi(wsi);
 }
 
+extern "C" LWS_VISIBLE int
+lws_plat_change_pollfd(struct libwebsocket_context *context,
+		      struct libwebsocket *wsi, struct libwebsocket_pollfd *pfd)
+{
+	lws_conn *conn = (lws_conn *)wsi->sock;
+	
+	(void)context;
+	if (pfd->events & POLLOUT) {
+		conn->awaiting_on_writeable = 1;
+		if (conn->writeable) {
+ 			mbed::util::FunctionPointer1<void, struct libwebsocket *> book(conn, &lws_conn::serialized_writeable);
+			minar::Scheduler::postCallback(book.bind(wsi));
+			lwsl_debug("%s: wsi %p (booked callback)\r\n", __func__, (void *)wsi);
+		} else {
+			
+			lwsl_debug("%s: wsi %p (set awaiting_on_writeable)\r\n", __func__, (void *)wsi);
+		}
+	} else
+		conn->awaiting_on_writeable = 0;
+	
+	return 0;
+}
+
 extern "C" LWS_VISIBLE int
 lws_ssl_capable_read_no_ssl(struct libwebsocket_context *context,
 			    struct libwebsocket *wsi, unsigned char *buf, int len)
 {
 	socket_error_t err;
 	size_t _len = len;
-
+ 
 	lwsl_debug("%s\r\n", __func__);
 	
 	(void)context;
-	/* s/s_HACK/ts/g when mbed3 listen payload bug fixed */
-	err = ((lws_conn *)wsi->sock)->s_HACK->recv((char *)buf, &_len);
+	err = ((lws_conn *)wsi->sock)->ts->recv((char *)buf, &_len);
 	if (err == SOCKET_ERROR_NONE) {
 		lwsl_info("%s: got %d bytes\n", __func__, _len);
 		return _len;
@@ -66,10 +105,6 @@ lws_ssl_capable_read_no_ssl(struct libwebsocket_context *context,
 #endif
 		return LWS_SSL_CAPABLE_MORE_SERVICE;
 
-	// !!! while listen payload mbed3 bug, don't error out if nothing */	
-//	if (((lws_conn *)wsi->sock)->s_HACK != ((Socket *)((lws_conn *)wsi->sock)->ts))
-//		return 0;
-
 	lwsl_warn("error on reading from skt: %d\n", err);
 	return LWS_SSL_CAPABLE_ERROR;
 }
@@ -78,10 +113,14 @@ extern "C" LWS_VISIBLE int
 lws_ssl_capable_write_no_ssl(struct libwebsocket *wsi, unsigned char *buf, int len)
 {
 	socket_error_t err;
+	lws_conn *conn = (lws_conn *)wsi->sock;
 
 	lwsl_debug("%s: wsi %p: write %d (from %p)\n", __func__, (void *)wsi, len, (void *)buf);
 	
-	err = ((lws_conn *)wsi->sock)->ts->send((char *)buf, len);
+	lwsl_debug("%s: wsi %p: clear writeable\n", __func__, (void *)wsi);
+	conn->writeable = 0;
+	
+	err = conn->ts->send((char *)buf, len);
 	if (err == SOCKET_ERROR_NONE)
 		return len;
 
@@ -121,6 +160,8 @@ void lws_conn_listener::start(const uint16_t port)
 int lws_conn::actual_onRX(Socket *s)
 {
 	struct libwebsocket_pollfd pollfd;
+	
+	(void)s;
 
 	pollfd.fd = this;
 	pollfd.events = POLLIN;
@@ -128,8 +169,6 @@ int lws_conn::actual_onRX(Socket *s)
 	
 	lwsl_debug("%s: lws %p\n", __func__, wsi);
 	
-	s_HACK = s;
-	
 	return libwebsocket_service_fd(wsi->protocol->owning_server, &pollfd);
 }
 
@@ -215,20 +254,36 @@ void lws_conn_listener::onDisconnect(TCPStream *s)
 	//if (s)
 	//delete this;
 }
+
+extern "C" LWS_VISIBLE int
+lws_plat_service(struct libwebsocket_context *context, int timeout_ms)
+{
+	(void)context;
+	(void)timeout_ms;
+
+	return 0;
+}
+
 void lws_conn::onSent(Socket *s, uint16_t len)
 {
 	struct libwebsocket_pollfd pollfd;
 
 	(void)s;
 	(void)len;
+	
+	if (!awaiting_on_writeable) {
+		lwsl_debug("%s: wsi %p (setting writable=1)\r\n", __func__, (void *)wsi);
+		writeable = 1;
+		return;
+	}
+	
+	writeable = 1;
 
-	pollfd.fd = this;
+	pollfd.fd = wsi->sock;
 	pollfd.events = POLLOUT;
 	pollfd.revents = POLLOUT;
-	
-	s_HACK = s;
 
-	lwsl_debug("%s: wsi %p\r\n", __func__, (void *)wsi);
+	lwsl_debug("%s: wsi %p (servicing now)\r\n", __func__, (void *)wsi);
 	
 	libwebsocket_service_fd(wsi->protocol->owning_server, &pollfd);
 }
diff --git a/lib/pollfd.c b/lib/pollfd.c
index b38df3d52..bdf0172a1 100644
--- a/lib/pollfd.c
+++ b/lib/pollfd.c
@@ -167,7 +167,10 @@ lws_change_pollfd(struct libwebsocket *wsi, int _and, int _or)
 	 *       ... and the service thread is waiting ...
 	 *         then cancel it to force a restart with our changed events
 	 */
-	if (pa.prev_events != pa.events) {
+#if LWS_POSIX
+	if (pa.prev_events != pa.events)
+#endif
+	{
 		
 		if (lws_plat_change_pollfd(context, wsi, pfd)) {
 			lwsl_info("%s failed\n", __func__);
diff --git a/module.json b/module.json
index f2c565edd..221e2994a 100644
--- a/module.json
+++ b/module.json
@@ -15,6 +15,7 @@
   "extraIncludes": [ "build/frdm-k64f-gcc/generated/include" ],
   "dependencies": {
     "mbed-drivers": "^0.11.1",
+    "sal-stack-lwip": "^1.0.4",
     "sockets": "^1.0.0"
   }
 }