Instructions
Double-check what kind of mod chip you have installed on your Wii.
Go to the mod chip's website and download the mod chip update. Burn it onto a DVD and put it into your Wii. Turn on the Wii and follow the instructions to update.
Turn on your Wii and connect it to the Internet. The Wii can only connect to the Internet through a Wi-Fi router. Go to "Internet" on the Wii menu and check the connection.
Check for a system update by going to "Wii System Update" from "System Settings." Also, if there is a system update available and your Wii is already connected to the Internet, the Wii console's light will flash to alert you.
Click on the available update. The Wii will tell you it is going to update your system. Press "OK."