Operation timed out after 30 seconds with 1524600 bytes received
Core and plugins auto-upgrade work fine now at slow connection. But I should to change timeout in function download_url() at wp-admin/includes/file.php to higher value. And after each update - change it again.
把 444行的 $response = wp_remote_get($url, array('timeout' => 30));
30改成300 或 600 后再次自动升级成功了