diff --git a/frontend/src/js/misc/wb-rootdir-wrapper.js b/frontend/src/js/misc/wb-rootdir-wrapper.js
index ed8c4b2..6fc5fcd 100644
--- a/frontend/src/js/misc/wb-rootdir-wrapper.js
+++ b/frontend/src/js/misc/wb-rootdir-wrapper.js
@@ -69,7 +69,7 @@ class WBRootDirWrapper {
       for (let i = start; i < end; i++) {
         const loc = stm[i];
         res.push([ loc[0], Math.max(0, seg[1] - loc[1]),
-          Math.min(loc[2], seg[1] + seg[2] - loc[1]) ]);
+          Math.min(loc[2] - loc[1], seg[1] + seg[2] - loc[1]) ]);
       }
       return res;
     }), file[1] ];
diff --git a/frontend/src/js/page/wb-download-page.js b/frontend/src/js/page/wb-download-page.js
index 4b1e748..c41c4b6 100644
--- a/frontend/src/js/page/wb-download-page.js
+++ b/frontend/src/js/page/wb-download-page.js
@@ -95,7 +95,7 @@ class WBDownloadPage extends Component {
           const blk = xhr_1.response.slice(loc[1], loc[2]);
           // const r = new Response(blk);
           // r.body.pipeTo(fileStream);
-          writer.write(new Uint8Array(blk));
+          return writer.write(new Uint8Array(blk));
         });
       }
       return prom_1;