diff --git a/lib/substream.js b/lib/substream.js
index ca058d2..4b4e4ff 100644
--- a/lib/substream.js
+++ b/lib/substream.js
@@ -7,11 +7,12 @@ function subStream(origin, length, pad, end) {
    var stream = new ReadableStream({allowHalfOpen: false});
    var readPadding = false;
    function _readPadding() {
+      if (readPadding) return;
       if (pad === 0) {
+         readPadding = true;
          end();
          return;
       }
-      if (readPadding) return;
       var data = origin.read(pad);
       if (data) {
          readPadding = true;