Bluetooth not working in Ubuntu 16.04 with [0cf3:3004] Atheros adapter
This problem exists because Atheros re-used the chip VID and PID.
See this bug report
As a workaround you can patch the btusb.c module and change it from ath3k to Rome.
I've built a DKMS package to fix this issue and uploaded it to my PPA.
https://launchpad.net/~hanipouspilot/+archive/ubuntu/bluetooth/+files/btusb-lp1542743-dkms_0.1_all.deb
Install this deb and reboot. This should fix the issue.