New flash cartridge is able to run 3DS software.
The first flash cartridge capable of running 3DS software has been announced. The Crown3DS is tested to work under current 3DS firmware 2.1.0-4, and the developers are in the process of testing it with more games. There is currently no time-frame for its release, with the developers' web site only saying that more info will be released "sooner or later."
The Nintendo 3DS Operations Manual contains strong warnings about using such devices, going so far as to say that "the use of an unauthorized device in connection with your system, will render the system permanently unplayable."