New firmware: how to control volume with bluetooth headset

Once the new firmware installed, all is working fine. I just noticed that the volume is too loud when the M8 is connected to the bluetooth hand free car headset. I succeeded to get M8 volume lower with the older firmware, but with the new one, even if I can use the volume button during call, the sound keeps staying too loud, and scratchy.
How to fix it?
Thanks.

just a guess but have you tried to change the volume of the music player during a call? definetely a bug but try to change that one!

No way... either with the car hand-free set or the blueooth a2dp headset, the volume does not change by using the volume player control... :-(
Hope the next fw will fix it.

e...
i will post your question to the official forum