• ASUSTek Computer, Inc. Broadcom BCM20702A0 Bluetooth
• ASUS Bt-400 0b05:17cd

[  489.427780] usb 3-7: new full-speed USB device number 9 using xhci_hcd
[  489.450343] usb 3-7: New USB device found, idVendor=0b05, idProduct=17cb, bcdDevice= 1.12
[  489.450345] usb 3-7: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[  489.450346] usb 3-7: Product: BCM20702A0
[  489.450347] usb 3-7: Manufacturer: Broadcom Corp
[  489.450348] usb 3-7: SerialNumber: 5CF3708AD929
[  489.561988] Bluetooth: hci1: BCM: chip id 63
[  489.562988] Bluetooth: hci1: BCM: features 0x07
[  489.578996] Bluetooth: hci1: BCM20702A
[  489.580014] Bluetooth: hci1: BCM20702A1 (001.002.014) build 0000
[  489.587827] bluetooth hci1: firmware: failed to load brcm/BCM20702A1-0b05-17cb.hcd (-2)
[  489.587828] firmware_class: See https://wiki.debian.org/Firmware for information about missing firmware
[  489.587830] bluetooth hci1: Direct firmware load for brcm/BCM20702A1-0b05-17cb.hcd failed with error -2
[  489.587831] Bluetooth: hci1: BCM: Patch brcm/BCM20702A1-0b05-17cb.hcd not found

Download BCM20702A1-0b05-17cb.hcd and put into /lib/firmware/brcm