You are right. I knew about the traveler's licence when you plan to leave Khartoum but totally I forgot.
It is difficult. In Ethiopia my Ethiopian fiancé and i have seen so many places as well as in the South. Anyhow after 7 times Ethiopia I am little bored by Ethiopia now, I will come back in November 2015, not earlier. In April we will meet each other in Thailand. Thailand is one of the less countries where it is easy for Ethio citizen to receive a 15-days-visa on arrival if some conditions are fulfilled, It was out spontaneous decision - flights, trains, transfers and hotels in Thailand are booked already, so I will not go to Sudan But thank you a lot for your advice.