Similar to your problem. I had CWM (PhilzTouch) and Cyanogenmod 10.2 nightly, it was working fine for long time until two weeks ago it rebooted on its own to the Download mode and won't go pass that. Odin can see it but says no PIT when I tried to re flash ICS or JB. Even when I flashed "and repartitioned" a working PIT for this model, Odin still could not complete the flashing for a reason I can't remember now. My tablet is now a big paper weight. Many on XDA suggested that eMMS or main board were hard bricked and I should take it to dealer, sadly it is outside warranty, and I am reluctant to pay a big $$$ to change the main board or eMMs. I really pray someone can give us some solution.