Well, that was a whole lot of alarmism for not much payoff.
A small fission weapon will not produce widespread, devastating EMP. That requires much larger fusion weapon(s). NK is nowhere near possessing such a weapon, much less miniaturizing it and fitting it to a missile.
Here is a good article on the Soviet 300 KT thermonuclear EMP tests over the occupied USSR:
http://www.futurescience.com/emp/test184.html
Note that the 300 KT weapons were about ten times larger than the largest NK has tested.
There you go again :)
The experts did mention hydrogen bombs. It’s a question of a different type of detonator. And you can bet whatever N. Korea has, Iran has.