There is actually a growing middle class - the Donju - earning money through the black market. They certainly have enough resources to (over)feed themselves - and buy expensive electronics.

As for the larger population, while most of the country still suffers from food shortages, starvation is not the problem it was in the 90s.

See for example: http://uk.reuters.com/article/2015/06/04/uk-northkorea-chang...

Didn't they switch to Kimograms? His grandpapi invented the unit, I believe.