Tplink firmware update can also be done through tplinkwifi.net and still if the user faces any kind of issue with this web link, then what you can do is try to access the Linksys web setup interface through the default IPs of 192.168.1.1 or 192.168.0.1 and authorize the tplink router login page.
http://tp-tplinkwifinet.net/