Many users have griped that the "Iron dagger" trick to get Smithing to 100 is now impossible due to the latest patch. It isn't impossible if you merely delete the update off your console. Go on your hard-drive, go on hard-drive options (x I think) and delete the cache. Next time you turn on Skyrim, you will be prompted to install the latest update. Say no, play the game offline without the update and do the Smithing power-leveling in your own time. When done? Install the update with your level 100.

That will only work if you start a new character without the patch. Once you install the patch and load up your character, and save the game thereafter, that save requires the latest patch to play.