'Pandora' of the PSP era, is now finally here for the Nintendo 2DS/3DS Family, plus it works on all 3DS firmwares!
Normmatt, kitlith, SciresM, hedgeberg and d3m3vilurr have released ntrboot_flasher for 3DS which was formerly known as MagnetPWN (MagnetHax).
Check the 3ds.guide website for full NTRBootHax instructions, and the forum thread over at gbatemp.net.
The DS flashcards supported so far are: Acekard 2i HW-44, Acekard 2i HW-81 and R4i Gold 3DS RTS, With planned support for: R4 SDHC Dualcore, Supercard DS2
Thanks goes to LameNobody for the heads up.