This method requires no software, no fancy router settings/models, and doesn't affect any other devices on your network. It works in sleep mode, too.
1. On your PC, go to OpenDNS.com and start up a free account: https://www.opendns.com/
2. add a network and use the default IP that shows up: https://dashboard.opendns.com/settings/
*This is your modem's IP, not your PC's IP. you can double check at http://www.whatismyip.com/
3. Click...
Blocking the 3DS from receiving the wifi update using OpenDNS
1. On your PC, go to OpenDNS.com and start up a free account: https://www.opendns.com/
2. add a network and use the default IP that shows up: https://dashboard.opendns.com/settings/
*This is your modem's IP, not your PC's IP. you can double check at http://www.whatismyip.com/
3. Click...
Blocking the 3DS from receiving the wifi update using OpenDNS