You're SOL -- the software responsible for acquiring the IP address is in flash. 3rd party solutions are unlikely to help you.

The problem seems to be this:

When the Receiver starts, it toggles on the Ethernet port for a short while to see if it can get link. If it can't, it then turns off the Ethernet port and turns on the HPNA port instead.

Some switches and routers don't respond quickly enough -- because they're busy doing 10/100 or duplex negotiation or some such nonsense, and so the Receiver gives up and turns off the Ethernet port.

The only reliable fix seems to be to use a 10Mbps hub instead of a dual-speed 10/100 hub, router or switch.

You should never need to reboot the server if it's a problem at the Receiver end. You don't have to pull the mains either -- just jab the power switch multiple times in quick succession.

And no, you can't assign a static IP to the Receiver (beyond telling your DHCP server to assign a permanent lease).