How do I block updates?
Use TubeHax DNS!! This will still allow you to use internet if you want, and only blocks Nintendo's update servers. It is ran by smea, who is very reputable in the 3DS hacking scene.
Set up TubeHax DNS on your Wii U:
1. Go to Wii U Menu/System Settings/Internet/Connect to the Internet
2. Input your router's SSID and password (typically WPA2-PSK AES)
3. Input settings as follows:
IP Address: Auto-obtain
DNS: Don't Auto-obtain
Primary DNS: 107.211.140.065 (TubeHax DNS)
Note: This will leave you unable to access YouTube
Secondary DNS: 0.0.0.0
Note: This should make your Wii U fail to connect to the internet if TubeHax fails, though it's not confirmed.
Additional preventative measures:
A. Block by URL Filtering (allows internet access still)
B. Block your Wii U's MAC Address (no internet access at all, can only run self-hosted files)
Note: Your router settings page is typically
http://192.168.1.1 or
http://10.0.0.1 A. Block by URL Filtering in your router settings
nus.c.shop.nintendowifi.net
nus.cdn.c.shop.nintendowifi.net
nus.cdn.shop.wii.com
nus.cdn.wup.shop.nintendo.net
nus.wup.shop.nintendo.net
c.shop.nintendowifi.net
cbvc.cdn.nintendo.net
cbvc.nintendo.net
B. Block your Wii U's MAC Address in your router settings
1. Go to Wii U Menu/System Settings/Internet/View MAC Address
2. Type the string you see into your MAC address filter (Ex: b8-ae-4e-48-36-fe)