Not unless a superpower enforces it, as is the case of Ethiopia losing Eritrea after the collapse of the USSR, or Sudan. Of course, in the Cold War, when you're being heckled by a side who wants to partition you, chances are, the other superpower would become your new best friend.
Odds are, virtually no leader, especially in Africa, would willingly give up land to separatists. South Africa under apartheid, maybe (they did claim that the Bantustans were independent protectorates as a way of disenfranchising Africans in the country). Other than that, not really.