Then I realized that the COM ports are not routed into WSL. I need USB-to-RS232 converters to interface with our hardware. Of course, there is a web of contradictory blog posts and announcements when that feature will be finished - one post stating if I upgrade to Creators Update MVP Edition 120394782034785023845 Build 23904782390475 or later, I can use the feature! It took me 1h to find out what version and build of Windows I had, and 1 hour to install the new Creators Update, and 1h to reinstall WSL - and guess what, the feature was absent. What a clusterfuck.