FYI, I was able to load the online zombies multiplayer loading configurable usb loader using cIOS249v20[56] (yes, i said FIFTY-SIX!) and launching the game using cIOS224v5[57] (yes i said v5 not v5.1).
However, I was not able to connect to multiplayer online using the above configuration (or the recommended configuration), but I did not get an error. I even tried creating a second profile, but that didn't work... I think it was an issue with ninty servers, I'll have to try again later and see if it works under the same settings.
FYI, I also tested recommended settings (launching cfg usb loader using cIOS249v20[56] and launching the game using cIOS224v5.1[57]) and it worked exactly the same as the settings I described above.
I also tried launching the game using cIOS249v20[56] and it did not work, it hung on the loading screen before even loading the main menu.