I had posted this question on 14 Sept in the “Usage and Firmware updates” under the “SD card instructions” discussion, but maybe it belongs here better; I can also provide more info.
Problem is similar to that described by kevin_s: the updater just does not run.
I’m running Vista Home Premium, Java 1.7 update 40, have the USBtinyisp installed. Hardware is OpenSprinkler v2.0 (May 2013), s/w version 2.0.0. Because hosting the js files on the SD card is not supported before 2.0.3, I am trying to upgrade the s/w version. I downloaded and extracted the Firmware Updater 2.0.zip. In folder osFirmwareUpdater/windows I see file osFirmwareUpdater.exe. But when I plug in the OS to USB, the updater does not run. The OS shows the date with “connecting…”, which then changes to “MC:__________________” after several seconds. If I try to run the .exe file, with or without OS plugged in, nothing happens.
Just for fun, I tried the instructions for OS v2.1: When I power the OS with B2 pressed, the screen shows “Reset All?”. That doesn’t seem to be what I want.