
Use a game that comes bundled with the 4.5 update. It's the only way to update to 4.5. Animal Crossing: New Leaf is an example of such a game.
I updated with GW_Release_1.0 using Luigi's mansion USA rom. No problem at all, and quickly done.


So the only way to update using a rom is on gw release 1.0, other then that you need a retail game?