I recommened you try our Unified firmware which is the offical firmware for the device. The preconfigured SD card has not been updated in a while which is why it is not on the SD card yet.
More information regarding how to change over is available here: https://opensprinkler.com/forums/topic/announcing-opensprinkler-unified-firmware-2-1-4/
Try that out instead and see if everything works.
Update: As a quick instruction to get up and running: just use a new Raspbian SD image burnt to a card and install by following these steps:
1) git clone https://github.com/opensprinkler/opensprinklergen2
2) cd opensprinklergen2
3) ./build.sh ospi