Do you have OpenSprinkler 2.1 or 2.0? The main difference (in appearance) between them is that 2.1 uses an orange-colored 24V AC terminal block, while 2.0 uses green-colored. The ‘pressing B2 while plugging in USB’ is only needed for 2.1 (due to its bootloader implementation). If you have 2.0, you do NOT need to press B2.