diff --git a/src/mux_h1.c b/src/mux_h1.c
index c55f6c4..cefba3d 100644
--- a/src/mux_h1.c
+++ b/src/mux_h1.c
@@ -373,7 +373,7 @@
 		return 0;
 	}
 
-	if (!(h1c->flags & (H1C_F_IN_ALLOC|H1C_F_IN_FULL|H1C_F_IN_BUSY)))
+	if (!(h1c->flags & (H1C_F_IN_ALLOC|H1C_F_IN_FULL)))
 		return 1;
 
 	TRACE_DEVEL("recv not allowed because input is blocked", H1_EV_H1C_RECV|H1_EV_H1C_BLK, h1c->conn);
@@ -1454,6 +1454,9 @@
 	if (h1s->flags & errflag)
 		goto end;
 
+	if (h1c->flags & H1C_F_IN_BUSY)
+		goto end;
+
 	do {
 		size_t used = htx_used_space(htx);