Either SSID will work. "attwifi" still works as Homepass relay. The difference is, that "attwifi" is no longer recognized as a Nintendo Zone, which means it won't cause the NZone icon to glow, and you won't be able to use it as an internet source (i.e. browsing, EShop, etc.) - but receiving and passing Streetpass data still works via the "attwifi" SSID. The downside to using "attwifi" is of course, no internet access via the Homepass relay. And if you are trying to emulate the Nintendo Zone for the sake of getting special rewards (i.e. Animal Crossing monthly gifts). If you wish to have an actual Nintendo Zone, then you need to use the "NZ@McD1". This is a German based Nintendo Zone, and will work fine in place of "attwifi" if you wish.