diff --git a/src/mux_h2.c b/src/mux_h2.c
index eeaa0c1..806c817 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -2442,11 +2442,34 @@
 	}
 
 	do {
-		max = buf->size - b_data(buf);
+		int aligned = 0;
+
+		if (!b_data(buf) && (h2c->proxy->options2 & PR_O2_USE_HTX)) {
+			/* HTX in use : try to pre-align the buffer like the
+			 * rxbufs will be to optimize memory copies. We'll make
+			 * sure that the frame header lands at the end of the
+			 * HTX block to alias it upon recv. We cannot use the
+			 * head because rcv_buf() will realign the buffer if
+			 * it's empty. Thus we cheat and pretend we already
+			 * have a few bytes there.
+			 */
+			max = buf_room_for_htx_data(buf) + 9;
+			buf->head = 0;
+			buf->data = sizeof(struct htx) - 9;
+			aligned = 1;
+		}
+		else
+			max = b_room(buf);
+
 		if (max)
 			ret = conn->xprt->rcv_buf(conn, buf, max, 0);
 		else
 			ret = 0;
+
+		if (aligned) {
+			buf->data -= sizeof(struct htx) - 9;
+			buf->head  = sizeof(struct htx) - 9;
+		}
 	} while (ret > 0);
 
 	if (h2_recv_allowed(h2c) && (b_data(buf) < buf->size))