Thanks for the info.
I use version 15.09 - Supermoon Eclipse.
I flashed it through its vehicle setup wizard.
This is the history:
A few days ago, I flashed it and was able to have the motors running. After installing the propellers, I tried it.
The results: it flipped to the right like a right roll. Broke one blade of a propeller.
Thinking that something was wrong with loading the firmware. I reloaded the firmware yesterday. It does not work anymore.
"Unresponsive" mean the copter doesn't respond to the transmitter. The light was on - solid red and flashing blue. When I turned on the transmitter, the lights on the copter stay the same.
I was able to rescue, then upgrade and erase this morning as suggested. Went through the whole procedure of setting the vehicle wizard.
The problem is: I cannot now calibrate the ESC and set up the transmitter. The first time ( a few days ago) I was able to calibrate the ESCs, but not now.