The firewall was on.
Turned it off, and the EZServ was able to download the .bin file from it.
Then… nothing. After several minutes, cannot get to the device either at 192.168.1.125 or the original static IP I had assigned it.
Added: Tried initially with the 2.0 firmware .bin. Then with the 1.6 firmware .bin. Same results. The device is still inaccessible.