Success!
Thanks Jeff Hass, I had to do it on a WIFI connected laptop;
Laptop -> WIFI router -> OpenSprinkler
Logistically its better too, take the laptop to the controller, download the latest OS binary, download the latest controller config file, update the firmware, reconnect the controller to your WiFi, press controller button 1, reopen the web interface, change the password, reimport the config, all good to go. You could do it in 2 minutes.
Thanks for Jeff and Ray’s help.