Jabra 8040 problems with updating
You will still be able to answer and end calls and talk on the phone and play streaming audio from the media player. If you have other devices (in car bluetooth, other headsets, etc) you won't have the ability initiate calls, etc and if the only profile that exists on the other devices in Handsfree profile then it won't even connect.
You can switch the Handsfree profile on and off through the Bluetooth menu but be prepared to do this everytime you switch between the BT8040 and your other devices.
I'm stuck in the step 4 / 5 when it says about the DFU.
And for those who lose important data like contacts, messages, notes and more, try How to Recover Data After i OS Update guide.
In beginning Bluetooth may just working well on your i Device.
I have tried to reset my headset to the factory default and still the same result.
I notice when I go to the device manager, I can see the yellow exclamation mark for Jabra BT8010 DFU Mode.