diff --git a/src/mux_h1.c b/src/mux_h1.c
index bed2e03..29ac930 100644
--- a/src/mux_h1.c
+++ b/src/mux_h1.c
@@ -3432,6 +3432,7 @@
 		goto end;
 	}
 
+	h1c->flags |= H1C_F_WANT_SPLICE;
 	if (h1s_data_pending(h1s)) {
 		TRACE_STATE("flush input buffer before splicing", H1_EV_STRM_RECV, cs->conn, h1s);
 		goto end;