Nothing is difficult. The point is that there is no excuse for using a) windows, b) freedos, c) geteltorito, or any hacks and workarounds in 2020 for updating the bios of your laptop.

To your point, the method of putting the bios file on a usb stick is also not universal. I don't think any lenovo laptops support that. And while passable, that's also kludgy.