In message f608b67d0703091448m3d109ebeyc5c3165d506d6a33@mail.gmail.com you wrote:

what happens if all interfaces are failing - does it come back to ethprime after trying them all and stops or does it keep trying until stopped by the operator with an arbitrary interface as the current one?

It continues cycling through the configured interfaces.

That seemed to have happened to me: I tried using an interface, it did not work, I went to see what happened, turned out the hub was down, but after I brought the hub back online the thing still didn't work - why - another interface became "current"!

If you had waited for the second inteface to time out you would have seen that U-Boot re-tried the first one which then should have worked.

Also, in some situations it is harmful to expose internal IP addresses on an external network - but u-boot would never have a second though about it :-)

It would not even have a first thought, as U-Boot never "exposes" any IP addresses if you use appropriate protocols like DHCP or BOOTP. All it "exposes" is it's MAC address.

Best regards,

Wolfgang Denk