When they got to the Naivasha accord in 2005, there was an impasse on this. This was the most that the north could concede, that there would be popular consultations.
What that means is not immediately clear. I know that the Sudan Council of Churches thinks that the aspirations of the majority of the people in the southern Kurdufan and Blue Nile will probably not all be met. But it was a compromise worked out when the CPA was finalized. So there is no straightforward answer other than....
Now, the elections were thought to be inadequate in the Blue Nile, at least by the Sudan Council of Churches and the rest of civil society in southern Sudan. Popular consultations happen, but it's the legislators who make the decisions. You can see that's already going to be a flawed outcome.
In southern Kurdufan province, things are moving very slowly. They haven't even elected the representatives who are going to vote after the popular consultation, so it's indeed a difficult situation.