Note that after you click on ‘Detect Device’, the controller will exit bootloading mode, therefore you will need to re-enter bootloading mode before clicking on ‘Upload Firmware’. If you already know your OpenSprinkler hardware version (2.1 according to you), there is no need to click on ‘Detect Device’ — you can simply select the hardware version from the dropdown list — the ‘Detect Device’ feature is really meant for users who don’t know or forgot which version they have.