diff --git a/lib/libwebsockets.h b/lib/libwebsockets.h
index e51052bb..90bf652e 100644
--- a/lib/libwebsockets.h
+++ b/lib/libwebsockets.h
@@ -3687,6 +3687,7 @@ struct lws_process_html_args {
 	int len; /**< length of the original data at p */
 	int max_len; /**< maximum length we can grow the data to */
 	int final; /**< set if this is the last chunk of the file */
+	int chunked; /**< 0 == unchunked, 1 == produce chunk headers (incompatible with HTTP/2) */
 };
 
 typedef const char *(*lws_process_html_state_cb)(void *data, int index);
diff --git a/lib/output.c b/lib/output.c
index 525ba109..5885c66f 100644
--- a/lib/output.c
+++ b/lib/output.c
@@ -663,8 +663,9 @@ 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->http.tx_content_remain)
-			poss = wsi->http.tx_content_remain;
+		if (wsi->http.tx_content_length)
+			if (poss > wsi->http.tx_content_remain)
+				poss = wsi->http.tx_content_remain;
 
 		/*
 		 * if there is a hint about how much we will do well to send at one time,
@@ -717,12 +718,13 @@ LWS_VISIBLE int lws_serve_http_file_fragment(struct lws *wsi)
 			lws_set_timeout(wsi, PENDING_TIMEOUT_HTTP_CONTENT,
 					context->timeout_secs);
 
-			if (wsi->sending_chunked) {
+			if (wsi->interpreting) {
 				args.p = (char *)p;
 				args.len = n;
 				args.max_len = (unsigned int)poss + 128;
 				args.final = wsi->http.filepos + n ==
 					     wsi->http.filelen;
+				args.chunked = wsi->sending_chunked;
 				if (user_callback_handle_rxflow(
 				     wsi->vhost->protocols[
 				     (int)wsi->protocol_interpret_idx].callback,
@@ -745,7 +747,7 @@ LWS_VISIBLE int lws_serve_http_file_fragment(struct lws *wsi)
 			}
 #endif
 			m = lws_write(wsi, p, n,
-				      wsi->http.filepos == wsi->http.filelen ?
+				      wsi->http.filepos + amount == wsi->http.filelen ?
 					LWS_WRITE_HTTP_FINAL :
 					LWS_WRITE_HTTP
 				);
diff --git a/lib/private-libwebsockets.h b/lib/private-libwebsockets.h
index 80f22401..04b312ca 100644
--- a/lib/private-libwebsockets.h
+++ b/lib/private-libwebsockets.h
@@ -1921,6 +1921,7 @@ struct lws {
 	unsigned int cache_intermediaries:1;
 	unsigned int favoured_pollin:1;
 	unsigned int sending_chunked:1;
+	unsigned int interpreting:1;
 	unsigned int already_did_cce:1;
 	unsigned int told_user_closed:1;
 	unsigned int waiting_to_send_close_frame:1;
diff --git a/lib/server/server.c b/lib/server/server.c
index 5bb8ee11..aa76e171 100644
--- a/lib/server/server.c
+++ b/lib/server/server.c
@@ -531,7 +531,9 @@ lws_http_serve(struct lws *wsi, char *uri, const char *origin,
 		n = (int)strlen(path);
 		if (n > (int)strlen(pvo->name) &&
 		    !strcmp(&path[n - strlen(pvo->name)], pvo->name)) {
-			wsi->sending_chunked = 1;
+			wsi->interpreting = 1;
+			if (!wsi->http2_substream)
+				wsi->sending_chunked = 1;
 			wsi->protocol_interpret_idx =
 					(char)(lws_intptr_t)pvo->value;
 			lwsl_info("want %s interpreted by %s\n", path,
@@ -1125,6 +1127,7 @@ lws_http_action(struct lws *wsi)
 		args.len = uri_len;
 		args.max_len = hit->auth_mask;
 		args.final = 0; /* used to signal callback dealt with it */
+		args.chunked = 0;
 
 		n = wsi->protocol->callback(wsi,
 					    LWS_CALLBACK_CHECK_ACCESS_RIGHTS,
@@ -2865,17 +2868,19 @@ lws_serve_http_file(struct lws *wsi, const char *file, const char *content_type,
 		return -1;
 #endif
 
-	if (!wsi->sending_chunked) {
-		if (lws_add_http_header_content_length(wsi,
-						       total_content_length,
-						       &p, end))
-			return -1;
-	} else {
-		if (lws_add_http_header_by_token(wsi,
+	if (!wsi->http2_substream) {
+		if (!wsi->sending_chunked) {
+			if (lws_add_http_header_content_length(wsi,
+						total_content_length,
+					       &p, end))
+				return -1;
+		} else {
+			if (lws_add_http_header_by_token(wsi,
 						 WSI_TOKEN_HTTP_TRANSFER_ENCODING,
 						 (unsigned char *)"chunked",
 						 7, &p, end))
-			return -1;
+				return -1;
+		}
 	}
 
 	if (wsi->cache_secs && wsi->cache_reuse) {
@@ -3075,31 +3080,33 @@ skip:
 		sp++;
 	}
 
-	/* no space left for final chunk trailer */
-	if (args->final && args->len + 7 >= args->max_len)
-		return -1;
+	if (args->chunked) {
+		/* no space left for final chunk trailer */
+		if (args->final && args->len + 7 >= args->max_len)
+			return -1;
 
-	n = sprintf(buffer, "%X\x0d\x0a", args->len);
+		n = sprintf(buffer, "%X\x0d\x0a", args->len);
 
-	args->p -= n;
-	memcpy(args->p, buffer, n);
-	args->len += n;
+		args->p -= n;
+		memcpy(args->p, buffer, n);
+		args->len += n;
 
-	if (args->final) {
-		sp = args->p + args->len;
-		*sp++ = '\x0d';
-		*sp++ = '\x0a';
-		*sp++ = '0';
-		*sp++ = '\x0d';
-		*sp++ = '\x0a';
-		*sp++ = '\x0d';
-		*sp++ = '\x0a';
-		args->len += 7;
-	} else {
-		sp = args->p + args->len;
-		*sp++ = '\x0d';
-		*sp++ = '\x0a';
-		args->len += 2;
+		if (args->final) {
+			sp = args->p + args->len;
+			*sp++ = '\x0d';
+			*sp++ = '\x0a';
+			*sp++ = '0';
+			*sp++ = '\x0d';
+			*sp++ = '\x0a';
+			*sp++ = '\x0d';
+			*sp++ = '\x0a';
+			args->len += 7;
+		} else {
+			sp = args->p + args->len;
+			*sp++ = '\x0d';
+			*sp++ = '\x0a';
+			args->len += 2;
+		}
 	}
 
 	return 0;