Unfortunately, the power button doesn't work and I'm not able to power off the device.
The only way, is physically pull out the battery, but if I'll do so, I wont be able to power it on again.
The cellular network doesn't work , and the Wi-Fi seems to, too.
The device is on for 53:21:59 hours!! (and seems to count..)
I must force somehow a reboot.
Is there shell command (and if so - how to access it?) , or application that forcing reboot?