diff --git a/src/mux_h2.c b/src/mux_h2.c
index af2ee17d1..672bc8ff3 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -2489,8 +2489,7 @@ static void h2_shutw(struct conn_stream *cs, enum cs_shw_mode mode)
 /* Decode the payload of a HEADERS frame and produce the equivalent HTTP/1
  * request. Returns the number of bytes emitted if > 0, or 0 if it couldn't
  * proceed. Stream errors are reported in h2s->errcode and connection errors
- * in h2c->errcode. The caller must already have checked the frame header and
- * ensured that the frame was complete or the buffer full.
+ * in h2c->errcode.
  */
 static int h2_frt_decode_headers(struct h2s *h2s, struct buffer *buf, int count)
 {
@@ -2509,6 +2508,9 @@ static int h2_frt_decode_headers(struct h2s *h2s, struct buffer *buf, int count)
 		return 0;
 	}
 
+	if (h2c->dbuf->i < h2c->dfl && h2c->dbuf->i < h2c->dbuf->size)
+		return 0; // incomplete input frame
+
 	/* if the input buffer wraps, take a temporary copy of it (rare) */
 	wrap = h2c->dbuf->data + h2c->dbuf->size - h2c->dbuf->p;
 	if (wrap < h2c->dfl) {
@@ -2755,9 +2757,6 @@ static int h2_rcv_buf(struct conn_stream *cs, struct buffer *buf, int count)
 	if (!h2c->dbuf->size)
 		return 0; // empty buffer
 
-	if (h2c->dbuf->i < h2c->dfl && h2c->dbuf->i < h2c->dbuf->size)
-		return 0; // incomplete input frame
-
 	switch (h2c->dft) {
 	case H2_FT_HEADERS:
 		ret = h2_frt_decode_headers(h2s, buf, count);