Calling from Nitdroid is still work in progress, as mentioned in the 4.1.1 announcement.

And hello,

Bumping this thread because I have a similar problem to OP's – N9 won't boot, LED does not flash, is undetected via USB.

I have tried the guide on everythingn9, but with no avail (on Win7 Enterprise):

• Navifirm can't connect to firmware server (auth error, have to get back on this because I am at work atm)

• Flasher won't start

Luckily I found the flashing N9 wiki via search. I shall keep you posted with progress.