"no networks found" problem.

hi.

I purchased a fire phone (AT & T unlocked) through eBay.

And I used normally four hours through a firmware update for 4.6.1 (including call and data)

But, unfortunately, as an update to the firmware of ..4.6.4 not normally use (the mobile network itself unusable state.)

Although recognized as a problem of the first firmware and carried by the downgrade version 4.6.3 through the ADB, the problem has not been solved.
Even then downgrade to 4.6.1 version is still not available.

I check the logs through*";dm" command, was able to confirm that awful crash logs are generated.

Is there any way to initialize the fire phone through the adb?
(Factory reset the recovery mode does not help at all.)

Does one have experienced solve this problem?
Current and using a carrier KT in Korea, and another fire phone is seen to be operating normally, USIM is normally available.

The first mobile network operating normally seen as something that seems to be a twist in the firmware update process internally with fire phone.

In summary, the present problem as follows.

1. Normal operation after first being released in the 4.6.1 firmware.
2. 4.6.4. After the firmware Firmware Update is disabled (mobile network unavailable)
3. 4.6.1 firmware downgrade - Mobile network still impossible
4. Select Networks Operator - no networks found

:crying::crying::crying::crying::crying::crying::c rying::crying::crying::crying::crying: