There is no more specific recovery tool than Cisco's recovery tool.

At the first, you need to verify that packets are sent from your computer to phone. Use packed catcher (like wireshark or so)  on your OTHER computer connected in the same network. I you will not see multicast packet sent by recovery tool, then it's problem either with the computer running recovery tool (firewall, multicasts blocked or so) or with your LAN infrastructure (multicasts blocked on switch or so).

If you will see multicast packeds from recovery tool, then run packet catcher on the same computer as recovery tool. Verify that you will see responses from phone. If no, then phone is not connected correctly or it is definitelly broken. Note that phone will respond to recovery request only after it is turned on. Use power cycle to be sure the phone is listening for recovery requests.

If you will see responses from phone, then we know there is working bidirectional path between PC with recovery software and PC. Then leave note here, I will write next steps.

Also note . It may give you some hints about expected data flows during recovery process.

Or ...

.. forgot all those advices and bring the device to authorized service centre ...