ReadyNas NV+ Boot Help

I have acquired a Netgear ReadyNas NV+ from a relative who no longer needs it, and am seeking some clarification on disk hardware. Can somebody confirm that this unit will only boot correctly with at least on hard disk in position No.1 and of the type listed in the HCL.
At the moment it is not responding to booting with an non listed 500gb Seagate drive, and will not respond to a firmware reload either.
It appears to enter the correct sequence during boot up but then just displays 'BOOTING' on the LCD display with the Blue power light flashing slowly.
I have tried to load firmware V4.1.7 via the front USB port, and it seems to start by reading the USB stick then just sits for hours 'processing'. I have tried various USB sticks and followed the method of writing the image to the stick as given in this forum.
I have noticed that also no indicator light appears on the Network Port at the rear of the unit, either if I connect this to my existing network through a ProCurve Switch
or directly to a Laptop Ethernet port.

I was lead to believe this unit did work with its previous owner but as he has emigrated I am not able to get much help in setting this up again. Any pointers would be appreciated

Thanks IK