Please check this page:
http://wiki.gbatemp.net/wiki/MT-Card
Latest fully working EmuNAND System version:
7.1.0 (NATIV_FIRM v12916)(Online is working as long as you don't need access to eshop)
So, if you want to use emunand, you'd better use Gateway 3DS now, or wait MT update
though gateway put kill code some days ago(because someone released fake gateway), they have removed the kill code for a long time,
it is safe now.