Hi guys, I recently bought a second hand Hyundai i20 Sound Edition. The machine is equipped with an AVIC-F840BT as standard. The device seems to work normally (gps or radio functions normally), but it is not possible to change any settings (for example, devices cannot be associated with bluetooth) and even trying to reset the device, it is not possible to enter the password because the keyboard is disabled. Anyone have any idea how changes can be enabled? Thanks.