I said a while ago that the altitude adaptations in Tibet were too damn good, more effective than those seen in Andean Amerindians, and so must have originated in a population that lived at high altitude for a long time. This seems to be the case.
The same must be true of Ethiopia. Their altitude adaptations also work well. There is a genetic component in Ethiopia that seems to correspond to the original hunter-gatherers, and the altitude alleles must have originated in that population, not the later components that look like East Africans or Levantines.
In both cases, there’s a fair chance that the ultimate origin could be some archaic group.