There’s a fairly well-known bug that causes the kit to give an ''Remote DFU Invalid CRC” error when trying to connect. The company has already addressed this issue a while back and has also provided a simple workaround to help fix the error on their forums.  If you experience this issue, following these steps can help you get rid of the error: Start with pressing down on the sensor’s power button. Hold it until the yellow light starts flashing. Once you see that yellow light, then it means that the sensor is now in update mode.  Open the Sensorware app on iOS or Android. You should be able to spot the sensor detected in update mode. If the sensor is detected, press OKAY to go to the update screen, then press UPDATE. It will take about 60-90 seconds to update the latest firmware to the sensors. Do not turn off or disturb the app while updating.  Once the update is over, restart the device and try to connect again. In case you are still facing issues with the device, contact Freedrum support, as you may be dealing with a manufacturing defect.