T38G transfer failed

[Barnabas]

Hello,

We shipped 4 new T38G phones 6 months ago to one of our customers. The phones worked fine last few months until we got calls from our customer last week complaining about transfer problem.

When an external call is received (say at extension 7020) and the operator tries to transfer the call to another extensions (say 7021) by dialing Transfer-7021-Transfer, the display of 7020 shows "transfer failed". Extension 7021 hears the ring but when she answers the call she hears the voice of 7020, not the outside caller. The outside caller hears MOH for a few seconds then there is complete silence. This happens 50% of the time. It happens to all other four phones as well.

All the phones came with the latest firmware 38.70.0.125. After hearing about this problem we tried upgrading the firmware on 7020 to 38.70.0.171 (AlloyCP RPS version) through our provisioning server. The logs show that extension 7020 downloaded all 3 files (MAC.cfg, y000000000038, and 38.70.0.171.rom) but it never upgraded to the new firmware.

Also, during the upgrade process the phone gets into a loop of downloading those 3 files repeatedly until I block the connection.

We logged remotely to a computer in that office and upgraded the firmware to 38.70.0.171. We also reset the phone so it downloaded the new configuration (through Yealink) RPS but the problem still exists. We tried upgrading a second phone but had exact same experience; firmware was downloaded multiple times (in a loop) but never got installed.

Please advise.

Thank you,
Barnabas