Nintendo is really late on this boat, not even sure why they are doing this now.
The 3DS was hacked a few years ago, but required a 4.5 or less version firmware.
Then like 2 years ago, a entry point was found under the 9.2 firmware, while 9.2 was the current firmware, and it was a community found exploit, which led to custom firmwares that didn't need hardware cards (like the Gateway or Sky). Since then we've had excellent work on hacking the 3ds, found multi entry points, homebrew entry points and other stuff. Best thing is the Freeshop, which allows you to download games for free off the eshop.
So ya, Nintendo is really late on this bus, mainly seeing as the Switch comes out in March 2017 and honestly the 3DS will probably stop being supported next year.