diff --git a/lib/server/parsers.c b/lib/server/parsers.c
index 2ae188c83..b75740c6f 100644
--- a/lib/server/parsers.c
+++ b/lib/server/parsers.c
@@ -1504,14 +1504,12 @@ handle_first:
 		 * if there's no protocol max frame size given, we are
 		 * supposed to default to context->pt_serv_buf_size
 		 */
-
 		if (!wsi->protocol->rx_buffer_size &&
 		    wsi->u.ws.rx_ubuf_head != wsi->context->pt_serv_buf_size)
 			break;
-		else
-			if (wsi->protocol->rx_buffer_size &&
-					wsi->u.ws.rx_ubuf_head !=
-						  wsi->protocol->rx_buffer_size)
+
+		if (wsi->protocol->rx_buffer_size &&
+		    wsi->u.ws.rx_ubuf_head != wsi->protocol->rx_buffer_size)
 			break;
 
 		/* spill because we filled our rx buffer */
diff --git a/lib/server/server.c b/lib/server/server.c
index 1b0def6e5..bb8d64efe 100644
--- a/lib/server/server.c
+++ b/lib/server/server.c
@@ -2867,18 +2867,31 @@ lws_interpret_incoming_packet(struct lws *wsi, unsigned char **buf, size_t len)
 		/* account for what we're using in rxflow buffer */
 		if (wsi->rxflow_buffer) {
 			wsi->rxflow_pos++;
-			assert(wsi->rxflow_pos <= wsi->rxflow_len);
+			if (wsi->rxflow_pos > wsi->rxflow_len) {
+				lwsl_err("bumped rxflow buffer too far (%d / %d)", wsi->rxflow_pos, wsi->rxflow_len);
+				assert(0);
+			}
 		}
 
 		/* consume payload bytes efficiently */
-		if (
-		    wsi->lws_rx_parse_state ==
+		if (wsi->lws_rx_parse_state ==
 		    LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED) {
 			m = lws_payload_until_length_exhausted(wsi, buf, &len);
 			if (wsi->rxflow_buffer)
 				wsi->rxflow_pos += m;
 		}
 
+		if (wsi->rxflow_buffer && wsi->rxflow_pos == wsi->rxflow_len) {
+			lwsl_debug("%s: %p flow buf: drained\n", __func__, wsi);
+			lws_free_set_NULL(wsi->rxflow_buffer);
+			/* having drained the rxflow buffer, can rearm POLLIN */
+#ifdef LWS_NO_SERVER
+			m =
+#endif
+			_lws_rx_flow_control(wsi);
+			/* m ignored, needed for NO_SERVER case */
+		}
+
 		/* process the byte */
 		m = lws_rx_sm(wsi, *(*buf)++);
 		if (m < 0)