diff --git a/tools/buildbot/bootstrap.py b/tools/buildbot/bootstrap.py
index 7cf536532..a62291240 100644
--- a/tools/buildbot/bootstrap.py
+++ b/tools/buildbot/bootstrap.py
@@ -92,7 +92,8 @@ def main():
             shutil.rmtree('OUTPUT')
         if not os.path.isdir('OUTPUT'):
             os.makedirs('OUTPUT')
-        run_shell(config_argv, env = build_env)
+        with Chdir('OUTPUT'):
+            run_shell(config_argv, env = build_env)
 
 if __name__ == '__main__':
     main()