This repo has 2 folders with self-descriptive names. Inside each of them is another README.md file with detailed instructions.
The main idea behind them was to fix the annoying problem of having to sit in front of a screen, to select the not-default Windows installation while I selected update and shutdown from the start menu. If I didn't do that, the computer would restart and boot into the default Windows installation, not finish updating the not-default one and not be shut down. Exactly the opposite of what I would except from the update and shutdown option 🙃. I hope it will be a useful tool for someone else as well.
*coded with having in mind only multi boots of Windows OSes using Windows Boot Manager