I have a normal DS and not a DSi. Also using the Datel DS AR, again not the DSi one, and none of the fixes or master codes work for me. (Game turns on and its white screen. No title or anything.) Guess gotta wait a few more days for link multiplier per fight.
These do work on ARDSi. And I can confirm every single code works except for the Reshiram event b/c the kid hasn't got that far.
elixirdream has posted instructions on how to enter the masters correctly. It involves making sure "mastercode" is the first line seen in the code. If you enter "(M)" manually as the name of the code, I believe this will be done automatically by the ARDSi.
He's also stated you may need to use one mastercode and one ARfix version.
If all else fails, I would enter both M codes and see if that tickles its wickles.
Why you people put so much effort into cheating in a VIDEO GAME is beyond me
Well, sometimes......people already beat the game, that isn't of their region, legit, and don't want to go through all of the trouble of super grinding to get back to where they were. Sometimes beating a game legit is near impossible, due to bugs (Ar Tonelico 2, I'm looking at you). Sometimes video games are made to be fun Sometimes, people use cheats to have fun playing video games, that are made to be fun. Maybe people don't have Wi-Fi, and have parents/spouses that are health nuts, so they can't go to McDonalds to get the two special episodes.
I dunno, just putting it out there
PSN: OniNoMeKyo, Currently Playing: Uncharted 3, Disgaea 4, and Hyperdimension Neptunia Mk 2, until Hyperdimension Neptunia V gets a US release