Hi folks,
my N9 (64gb, black, austria, two years old, screen replaced one year ago after a bad fall) is dead, but I would like to have a last diagnosis...

It was working perfectly, battery ~35%, I plugged it to wall charger and left it alone. 20 minutes later when I come back : screen is black, phone is not responding.

I cannot boot it. Battery led is :
- ON for a few seconds (nothing on computer, linux btw, dmesg)
- then OFF for a few seconds, less than in first step (computer detects "Nokia USB Rom")
- then ON again, we are back to step 1, computer sees a USB disconnection
Same thing under Win7 (devices manager).

Hardware manipulations :
- the only way to be sure to make it stop : unplug battery.
- I've tried with a new battery (an easily replaceable part), but I still have the same behavior.

Software manipulation :
- cannot be flashed by 'flasher', flasher -i does not see it
- same thing with Phoenix (under Win7)
- coldflash does not work, there is a timeout after first step http://pastebin.com/YVX8M2Sz

My diagnosis : hardware problem, next step to repair it is either http://i.imgur.com/aCaRQgc.png or http://i.imgur.com/KAAH8Pc.png

Any help is welcomed.

Sounds pretty dead to me, one thing to test would give hwid as flasher parameter, that way it doesnt need to be queried. But that would require you to know the hwid to begin with and to have flasher with --hw-revision=ARG support.

I've only seems HWID beeing nuked if someone has messed up the CAL either in secure mode or by using some other flasher than flasher 3.1.12. If you happen to break HWID then the device is a brick.

Internal flasher also has --set-hw-revision[=ARG] but I think thats only available on nokia care.