yes it's possible, it's probably what is explained in stickied threads.
add tubehax DNS to your network settings.
it will block updates, but allows online games if you are on latest firmware version.
if you are not, you have to either spoof (fake) the version so the game think you updated and allows online access, or just update to 5.5.1 and then use Tubehax DNS to block any future updates.