diff --git a/lib/output.c b/lib/output.c
index 61975c97..c7d9d8e3 100644
--- a/lib/output.c
+++ b/lib/output.c
@@ -507,7 +507,7 @@ send_raw:
 			     (wp & 0x1f) == LWS_WRITE_HTTP_FINAL) &&
 			    wsi->u.http.tx_content_length) {
 				wsi->u.http.tx_content_remain -= len;
-				lwsl_info("%s: content_remain = %llu\n", __func__,
+				lwsl_info("%s: wsi %p: tx_content_remain = %llu\n", __func__, wsi,
 					  (unsigned long long)wsi->u.http.tx_content_remain);
 				if (!wsi->u.http.tx_content_remain) {
 					lwsl_info("%s: selecting final write mode\n", __func__);
@@ -639,6 +639,9 @@ LWS_VISIBLE int lws_serve_http_file_fragment(struct lws *wsi)
 
 		poss = context->pt_serv_buf_size - n - LWS_H2_FRAME_HEADER_LENGTH;
 
+		if (poss > wsi->u.http.tx_content_remain)
+			poss = wsi->u.http.tx_content_remain;
+
 		/*
 		 * if there is a hint about how much we will do well to send at one time,
 		 * restrict ourselves to only trying to send that.