You may list all Bluetooth devices like this:
hcitool dev hciconfig hci1 up hcitool -i hci1 lescan dmesg | grep -i bluetooth dmesg | grep -i bluetooth | grep -i firmware
broadcom:
broadcom corp. bcm20702a0
https://github.com/winterheart/broadcom-bt-firmware/releases
The output may look like this:
Bluetooth: hci1: BCM: chip id 63
Bluetooth: hci1: BCM20702A
Bluetooth: hci1: BCM20702A1 (001.002.014) build 0000
bluetooth hci1: Direct firmware load for brcm/BCM20702A1-0b05-17cb.hcd failed with error -2
Bluetooth: hci1: BCM: Patch brcm/BCM20702A1-0b05-17cb.hcd not found
As you can see, you need brcm/BCM20702A1-0b05-17cb.hcd firmware.
Place required .hcd file to /lib/firmware/brcm and reboot your computer. After reboot you will see that firmware successfully loaded:
Bluetooth: hci1: BCM: chip id 63
Bluetooth: hci1: BCM20702A
Bluetooth: hci1: BCM20702A1 (001.002.014) build 0000
Bluetooth: hci1: BCM20702A1 (001.002.014) build 1467
Bluetooth: hci1: Broadcom Bluetooth Device
Congratulations, now your bluetooth device successfully loaded. Now go to Bluez for futher configuration.