No serial port identified on Boron

A few things here:

  1. you could try typing in the command:
npm install -g particle-cli

into the terminal in VS Code, not the Particle CLI. If that still doesn't work try #2

  1. Try to uninstall the Particle extension in VS Code, and try to re-install it via this link: Workbench | Getting Started | Particle

Also check out this link this for more.