Is this device working? Can you find any firmware updates for it?

The squashfs image appears to be truncated at 0xC80000.

_________________
A backup a day keeps DR away.

Yes, device is working.
I opened it without triggering tamper sensor.
UART port is not accepting any input.
I'm in Poland and it looks like at&t servers are not accepting connections from my ip address.
Servers addresses are dpewe-santa-clara.wireless.att.com cmhsne-columbia.wireless.att.com they should have port 443 (https) open, but I can't connect to it.
It is also possible that servers are turned off, but I can ping them, so something may be still working.