diff --git a/lib/platform/github/index.js b/lib/platform/github/index.js
index 00e0a6acb1..2eb8d3ac22 100644
--- a/lib/platform/github/index.js
+++ b/lib/platform/github/index.js
@@ -1141,11 +1141,14 @@ async function getFile(filePath, branchName) {
         logger.info('Cannot retrieve large files from non-master branch');
         return null;
       }
-      let treeUrl = `repos/${config.repository}/git/trees/${config.baseBranch}`;
-      const parentPath = path.dirname(filePath);
-      if (parentPath !== '.') {
-        treeUrl += `/${parentPath}`;
+      // istanbul ignore if
+      if (path.dirname(filePath) !== '.') {
+        logger.info('Cannot retrieve large files from non-root directories');
+        return null;
       }
+      const treeUrl = `repos/${config.repository}/git/trees/${
+        config.baseBranch
+      }`;
       const baseName = path.basename(filePath);
       let fileSha;
       (await get(treeUrl)).body.tree.forEach(file => {
diff --git a/test/platform/github/__snapshots__/index.spec.js.snap b/test/platform/github/__snapshots__/index.spec.js.snap
index a28409a4d1..2352841cfe 100644
--- a/test/platform/github/__snapshots__/index.spec.js.snap
+++ b/test/platform/github/__snapshots__/index.spec.js.snap
@@ -241,10 +241,10 @@ Array [
     "repos/some/repo/git/trees/master?recursive=true",
   ],
   Array [
-    "repos/some/repo/contents/backend/package-lock.json?ref=master",
+    "repos/some/repo/contents/package-lock.json?ref=master",
   ],
   Array [
-    "repos/some/repo/git/trees/master/backend",
+    "repos/some/repo/git/trees/master",
   ],
   Array [
     "repos/some/repo/git/blobs/some-sha",
diff --git a/test/platform/github/index.spec.js b/test/platform/github/index.spec.js
index 2e69f9a33e..245138fb3c 100644
--- a/test/platform/github/index.spec.js
+++ b/test/platform/github/index.spec.js
@@ -74,7 +74,7 @@ describe('platform/github', () => {
           },
           {
             type: 'blob',
-            path: 'backend/package-lock.json',
+            path: 'package-lock.json',
           },
         ],
       },
@@ -1644,7 +1644,7 @@ describe('platform/github', () => {
           content: Buffer.from('{"hello":"workd"}').toString('base64'),
         },
       }));
-      const content = await github.getFile('backend/package-lock.json');
+      const content = await github.getFile('package-lock.json');
       expect(get.mock.calls).toMatchSnapshot();
       expect(content).toMatchSnapshot();
     });
@@ -1663,7 +1663,7 @@ describe('platform/github', () => {
       }));
       let e;
       try {
-        await github.getFile('backend/package-lock.json');
+        await github.getFile('package-lock.json');
       } catch (err) {
         e = err;
       }