TEAC NT-505 impossible connecting to WiFi router o such LAN: help me please?

Hello mates,
I got my NT-505 3 days ago.
It seems to be working correctly but in my opinion all software in not the same level than the device: too aged & often no relevant documentation or support about.
However my big trouble is the NETWORK interface:  since first time I switched on, the NT-505 remains "for ever"  into NET configuring blinking state until it goes in power stand by.
Summarizing:

1. RJ45 cable is ok - tested in several manners
2. the wifi router (1Gb fiber connection) is ok
3. the wifi router ether ports (4) are ok - I checked a bridged LAN configuration too

Testing the NT-505 Ether port It results:

1. the physical level of protocol seems working correctly just on-way: the interface recognizes correctly the bandwidth (Fast ot Giga in my case) end the packet coming from the router are buffered. No packet sent  to the router.

2. At protocol level no ARP session are involved hence impossible retrieve MAC address and trying to do something.


VERY STUPID ISSUES:

1. Being NET board logically split from MAIN board It's need a separate firmware(!!!): how can I upload the NET firmware if, as stated into documentation, I must use the mobile app and It's impossible connecting the device to such LAN?

2. NO menu interface to configure manually the net parameters.

May someone help me (tricks..., recovery sw,..., low level maintance menu...,...) 

Thank you a lot.