1. Firmware not loading.

   dmesg | grep -i bluetooth
   
   bluetooth hci0: Direct firmware load for brcm/BCM20702A1-0b05-17cb.hcd failed with error -2

2. Download Windows driver from ASUS.
   http://dlcdnet.asus.com/pub/ASUS/wireless/USB-BT400/UT_USB_BT400_6516000.zip
3. Extract and open Win32\bcbtums-win7x86-brcm.inf
4. Find Product Name (BT400).

   %AsusBT400.DeviceDesc%=RAMUSB17CB,          USB\VID_0B05&PID_17CB       ; 20702 standalone

5. Find section for "RAMUSB17CB".

   ;;;;;;;;;;;;;RAMUSB17CB;;;;;;;;;;;;;;;;;
    
   [RAMUSB17CB.CopyList]
   bcbtums.sys
   BCM20702A1_001.002.014.1315.1347.hex
    
   [RAMUSB17CB.NTX86]
   Include=bth.inf
   Needs=BthUsb.NT
   FeatureScore=F0 …

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