It isn't a retail device. It came in an unmarked box. I have had my share of devices that were not supposed to be flashed over the last years and still managed to flash them. But this is a tough one. Cannot find a way to do this.
I have exactly the same problem. My device comes from the batch of the early prototypes and I can't flash it to a new firmware. Neither it updates to 7008 through Zune as it always says the phone is up-to-date.
Big shame, I'm stuck to the 7004... Any idea for solution?
Mine is too but it is updated to 7008. Guess I can update it to NoDo too with the instructions on the Omnia general forum. But the receptance is much better with the latest firmware. That is why I would like to upgrade.