We are working on this and did see something like this a few times. In those cases, it was a matter of rebooting(1-3 times) and have the board come up. Quite weird, and clearly we have not located the root cause yet, but we wanted to let you know. Let me know if you are able to get it up and running after a couple of power cycles.
We are working on releasing a new uImage that we have been running for a couple of weeks now. Many of the issues seem to have gone away, but we'll let you be the judge once we release it...
All sources will be delivered at the "parallella" github account: github.com/parallella
Andreas