'Aquire' the 3DS Devkit Tools (Intellectual property of Nintendo, can't discuss where to get it)
Rename devmenu.csu to devmenu.3ds and load it onto your gateway microSD
Put CIAs on your SD card. Boot emuNAND, launch devmenu and install at your hearts desire.
Also, Xenoblade Chonicals is packed with 9.4 system menu update.