Today it was different.
Awoke the display on by hitting the power button, phone unresponsive for long seconds, usual connection problem (why the heck it has to freeze the WHOLE UI!), then display went off, quickly blinking red light.
I thought it froze and was about to remove battery, when it (after few seconds of red blinking) switched to quick green flashing for a second or so and I was able to unlock and use the phone.

I think it crashed (WiFi module may be, but not so bad to kernel panic), the red blinking is probably a memory dump and the green one means he's sort of recovering.