1.Download latest firmware from website and unzip it to your local folder.
2.Press OK button on the keypad of your device (say T42S) to obtain the IP address.
3.Open your web browser (such as Chrome, IE or Firefox), input the IP address in the address bar and press enter.
4.You may find screen below asking for username and password. They are admin/admin by default.
5.Go to Settings—Upgrade, click the Browse button to choose the firmware that you already download.
6.Press Upgrade button. Following window will pop out. Please press OK to continue and wait about 5 minutes.
7After that, click OK button on keypad again to check whether the firmware has been successfully upgraded.