diff --git a/src/mux_h2.c b/src/mux_h2.c
index ad7c59f99..ff2d115f7 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -5212,7 +5212,7 @@ static int h2c_dec_hdrs(struct h2c *h2c, struct buffer *rxbuf, uint32_t *flags,
 		b_sub(&h2c->dbuf, hole);
 	}
 
-	if (b_full(&h2c->dbuf) && h2c->dfl) {
+	if (b_full(&h2c->dbuf) && h2c->dfl && (!htx || htx_is_empty(htx))) {
 		/* too large frames */
 		h2c_error(h2c, H2_ERR_INTERNAL_ERROR);
 		ret = -1;