Not really, this is really only for if your 3DS bricks for whatever reason, or if you want to downgrade and upgrade at your leisure.suiken_2mieu wrote:Is this for flashing the firmware to what ever you want?
You can't use another NAND from another 3DS(Yet), as each console's NAND is encrypted to the mainboard it's on.
What you can do, is back up whatever stable firmware that you have, keep it safe, and flash it back to the console.
The closest thing so far to flashing a somewhat custom firmware would be to flash emuNAND (Emulated NAND from an exploit based 3DS flashcart) to the console, but so far, that's only worked until 9.2.
I suppose you can do other things with it, like peek at the NAND dumps with exploratory surgery in a hex editor and whatnot.