Set your network settings on all existing connection to manual DNS (do not automatically DNS) and set the address as 107.211.140.065 for both. This is tubehax DNS, it will keep your system from updating.
When a game has a software update (smash, splatoon, mario maker etc) you can disable tubehax by reverting the setting to automatic, letting the game update and then launch, then exiting the game and setting the tubehax dns back up. It's annoying, but it will completely keep you from updating the system... and watching youtube.