So if my device node is /dev/sdb1 on Gentoo Linux, will the command look something similar to this?
// unmount 3DS nand if mounted
$ sudo umount /dev/sdb1
// Backup 3DS nand
$ sudo dd if=/dev/sdb1 of=nand.bin bs=1
// Restore 3DS nand
$ sudo dd if=nand.bin of =/dev/sdb1 bs=1
// unmount 3DS nand if mounted
$ sudo umount /dev/sdb1
// Backup 3DS nand
$ sudo dd if=/dev/sdb1 of=nand.bin bs=1
// Restore 3DS nand
$ sudo dd if=nand.bin of =/dev/sdb1 bs=1