Our current minimal drive size requirement in the installer is 1G.
While updating a test VM with a drive size set to 1G, I noticed that with current dev image, such machines may not have enough space to perform image upgrade. Even though release images will be smaller than dev builds with a set of debug tools, the point remains: 1G is too small to be practical.
I suppose we should bump the requirement to 2G. It's unlikely to cause problem for users of small hardware, since boards with built-in <2G flash are now too old to be practical, and less than 2G flash chips are hard to even find now, to the point that Ubiquiti was flashing 2G images to 4G chips apparently because they were easier to get, and cost the same.