I am thinking that did not instantaneously happen all
at once 2.4 billion years ago.
To the best of my understanding, I am thinking that most
of the world's iron ore deposits happened because iron is
much more soluble in water under conditions where carbon
dioxide is dissolved in the water in great amounts rather
than at a different ratio than what you would expect if
there were significant amounts of oxygen in the atmosphere
and much less carbon dioxide.
The starvation of some metal ions dissolved in the ocean
now for the production of organisms, which might be at
the bottom of the ocean kilometers deeper than the photic
zone near the top of the ocean, may be somewhat of a
limiting factor for life in the oceans now. Shallow
waters with somewhat more or less dissolveable particles near
the top sunlight layer tend to be more productive for life
and the microscopic photosynthetic algae that is
the basis of the food chain in the oceans often in
comparison with many deeper open waters.
In essence, iron had to precipitate out of the ocean before
the atmosphere could convert from carbon dioxide to oxygen
and nitrogen, and a lot of iron ore deposits date from as
recent as one and a half billion years ago. That is almost
a billion more recent than 2.4.
In general however, of course, oxygen producing photosynthesis
would have to be able to exist to BEGIN the process, so the start
of it might therefore of course be earlier.