Model :

Hardware Version : Not Clear

Firmware Version :

ISP :

Hi,
I have the following problem:
I connect 2 HD at the 2 USB ports, one works correctly (the first) but the second is instable, in the USB panel of administration software I see the second disk connected and immediately disappear, then connected again and disappear.
I have the firmware version 0.9.1.0.12 v002d.0 Build 150514 Rel. 33266n and hardware version Archer D7 v1 0000000000

Can someone help me to fix the problem?

Thank you!!

Fabrizio