The bloody problem is that I live in a God forsaken country that has no Nokia Care. I have to send it in for repair at one of the "authorised care centres". I would love to throw a fuss, but I don't even whether it would help. They can also claim that they don't speak English, and then I would be left with nothing to say.

Was gonna suggest the same thing

As expected, flashing didn't help. So back goes the device tomorrow ... thanks all.

I've got similar problem.
When my phone goes to Stand-by screen it won't wake up by double tapping or pushing on/off button. The clock stops after some time and stands still.
I'm able to awoke N9 only by restarting. Even if I turn off Stand-by Mode in Settings it goes the same.
Any ideas on how to fix it?

This could be a bit entrenching but it kinda looks like Nokia messes up things with N9s deliberately...as if they were ordered to totally doom any N9 that randomly shows up in their hands... there are more people complaining about Nokia Care services if N9s hit the place recently...
also, FW-wise, the whole PR1.3 update looks like it eventually brought some stupid bugs instead of some real improvement...though I can´t say my N9 acts weird or anything but reading about some bugs people are encountering makes me a little annoyed...

I've faced this issue and done hell lots of research.
I come out with these conclusions:

1) Tweaks issue: N9tweaks. If you don't have this installed, jump to 2nd conclusion.
2) Software issue: reflashing would solve.
3) Proximity sensor: Take it out and put them back, it works.

Try not to touch the hardware, do step by step, start off with reflashing.
Here's a guide,
http://www.youtube.com/watch?v=9dxsT...feature=relmfu
you may jump to 3:43 for how to take out proximity sensor.

All the best for people facing this problem.
PS: if problem still remains, sorry you gotta send them to Nokia Care, proximity sensor could be faulty. Mine was faulty right after they returned my phone, they change them straight away.

Work for me, Thanks