Living in a country that doesn't observe sanction niceties ...
I have worked in the DPRK repairing our companies equipment they purchased through government resellers.
Getting there requires a multiple-entry Chinese visa. I go through HongKong then use rail to the border. There are three border gates for non-tourists. Tourists have to travel to Pyongyang and Americans can only fly there from BeiJing.
As my DPRK visa states "Government Guest Worker" I can choose the gate nearest my destination - travel, food and accommodation is best on the Chinese side of the border. I prefer land travel - rail - as I usually have to carry test equipment. The DPRK trains I class as hard seat - worse than any aged UK train.
Since I am going to industrial DPRK I make sure I am well stocked with Chinese noodles as I don't like extremely spicy food. The DPRK customs inspection takes an age, uneducated inspectors gazing at awe at modern electronics. They seal my laptops - to be only opened at destination. Water-based glue is not very effective on plastic!
My visas are 'loose', stapled and not glued into my passport. (Glued visas are easily removed with acetone) This means I have deniability. Since I legally have several passports I leave China on one and enter the DPRK on another.
I have to be escorted, usually a female, from the border to the work centre. I have had the same female for the last several years, so we are now friends. Her English is excellent. I pack my equipment interiors with small, valuable, gifts to give away.
I carry large business cards on which is printed information about Canada and I give these to people who dare to shake hands and say 'Hello'! At the work centre things are very relaxed, but the food and accommodation is not good. They eat some very strange things!
There is a hunger for technical knowledge and we print out what I take since DPRK storage media is encoded and re-entering by hand circumvents these trackers. The customs might count SD chips but they can't count the contents! I usually leave
You can now use cell handsets in the DPRK - you buy a 'Foreigner' SIM that restricts your connections to other Foreigners and International calls. I use a multi-SIM Chinese handset and my customer gives me a DPRK resident SIM which allows me to contact DPRK users.
As I have been there numerous times over the past 7 years and my work place is somewhat distant from Pyongyang what I call the 'Communist bullsh*t' is more relaxed. The local techs invite me to their homes, along with my female guide. I often take my female guide, a widow with children, to dinner and she takes large 'doggy bags' home.
If any tech reader gets the opportunity to visit the DPRK - go. Just learn the rules. And leave whatever technical goodies behind as gifts when you leave. They appreciate even solder.
Also remember the DPRK gets bloody cold, as cold as Northern Canada, and the difference is they have minimal inside heating. Take warm clothes. Assume that there are no facilities there that you need for your work. And if you see a national entertainment group, such as the Moranbong Band (Moran Hill Orchestra) out in the regions, often there are only a few members of the main Orchestra there with back-ups picking up the slack.