This route has been tried by several teams in summer and winter.
1895, Alfred Mummery and two Gurkhas, Gorman Singh and Ragobir Thapa, headed up the Diama Glacier in an attempt to reach the northern or Rakhiot side of the mountain via a crossing of the 6,300m Diama Pass on the east ridge of Ganalo Peak but disappeared.
1990, Sepp Walter and team. Reaching the Diama Pass.
1991, Peter Wörgötter and Herbert Rainer. ~7400m
2000, Hanspeter Eisendle, Hubert and Reinhold Messner, and Wolfgang Tomaseth. Where they really have been is unclear as they don't want to provide useful information and just say that they are not sure about the elevation they reached. (possibly 7500m)
2008, Markus Gschwendt and Clara Kulich (Austria) could reach a high point of 7760m on ski.
2012, Simone Moro and Denis Urubko reached 6,800m during a winter ascant.
2014/15, Tomas Mackiewicz (Poland) and Elizabeth Revol (France)
From the first camp of the Kinshofer route head north and follow the Diama Glacier (do not confuse with Diamir which is south of that point) to an altitude of about 5900m.
Turn SE and climb the NW face of the Nanga Parbat north summit to about 7600m. Traverse out of the face to the right.
Huge seracs and crevasses are waiting on this route and in some years it can be impossible to to pass the Diama Glacier at all. In years with a lot of snow it can be just easy walking.
Big avalanches can be a danger on this route making it not easy to find save places for camps.