This evening, Debian Team pushed through a second kernel update, Following this one, earlier this morning, which applied to the computer I name ‘Phoenix’. The reader will be reassured to know, that every kernel update to version:
3.16.0-6-amd64
Results in version:
3.16.0-6-amd64
But this time, something rather remarkable happened:
The X-server started, directly on the first attempt! 
This means, that the problem which I was writing about above, may or may not have been solved, and the required reboot only took from 20h25 until 20h30.
Dirk
