Yes, it was leaked by a person who works for Nokia.
But that doesn't mean, that it was leaked intentionally by Nokia.
And to stop all the rumors that PR1.2 is the last update: no it is not, there will be AT LEAST one update after PR1.2

edit: now we can assume, that something is wrong with your eMMC. did you try to reflash it without the -R flag?
also you can try to put the N900 is R&D mode, then it should be possible to reflash the eMMC again.