I have an EthernetBlaster II that requires an older version of the firmware to be loaded because of compatibility constraints. 519_179 is the version I am trying to restore to. When I do load the firmware through the web interface the device becomes inoperable. I cannot connect to the configuration page, the status LED is "breathing" yellow, and the factory reset button does engage a reboot.
Could you try to hold the Machine Reset to see if you are able to reset the blaster? The reason is that you need to make sure that your blaster has green led before you are able to proceed with firmware changes.