Does it want to update when you start multiplayer for the first time?
YesThen it is normal, the update fixes some bugs found ingame like lagshooting, poor hit detection and ingame glitches therefore its safe to update
No, It says you need to update to the latest System Menu when starting MW3 channelIt is not safe to update
I have Mw3 for the wii aswell and it asked me for an update when I started multiplayer for the first time. It didn't brick my softmodded wii.