Dongola-Wadi Halfa, 453km, Monday-Saturday(12th-17th)
The heat became milder after Dongola along the river. I could ride in the afternoon again.

I crossed the Nile with a small boat called "Pandon".
There were more resting places than I expected. 2 in a day, at least. I didn't have to carry so much food and water.
Buying mineral water was getting difficult. They didn't sell it in a small shop of a village. (There were a few towns where I found a market or shops with more variety.) I started drinking Nile water in the earthenware jars in the villages. Natural Nile water. No chlorine, no filter. But I didn't have any trouble in my bowel.
They often had fried fishes in restaurants. That was nice. Beans was good too.

I quickly prepared for leaving. The immigration asked how many days I took in Sudan by bicycle. "17days." "Good on you." That was all.
Well, in fact, when I registered in Dongola, I also got "permission to travel to Wadi Halfa" at the immigration office. (I took "permission to cross Nile" too from the security police in another office. That was free.) The officers were nice and did it for me. They knew about my days, and said visa would be no problem. I didn't get anything special on my passport though. Just a regular registration sticker and a signature. I paid about $50, which seemed to be the fee for registration. Maybe it was just the phone call they made to Khartoum. I don't know. Anyway, it went fine.
$100 for transit visa, the $50, and the departure tax and the fare for the ferry. (I forgot how much.) Expensive 17 days. But it was a good experience.