For me on board bluetooth was showing but not working properly, was not able to connect any bluetooth devices. And
GBU521 IOGEAR Bluetooth 4.0 Adapter was also not working
Done below steps now
GBU521 IOGEAR Bluetooth 4.0 Adapter is working fine.
1) disable port limit in XHCI kext (credit DalianSky,Ricky), Mount EFI using Clover Configurator open config.plist from /Volumes/EFI/EFI/Clover in text editor like Sublime and add below code in KextsToPatch section
Code:
<dict>
<key>Comment</key>
<string>disable port limit in XHCI kext (credit DalianSky,Ricky)</string>
<key>MatchOS</key>
<string>10.14.1,10.14.2</string>
<key>Name</key>
<string>com.apple.driver.usb.AppleUSBXHCI</string>
<key>Find</key>
<data>g/sPD4OPBAAA</data>
<key>Replace</key>
<data>g/sPkJCQkJCQ</data>
</dict>
2) Disable on board Bluetooth in BIOS (see attached photo for reference)
Devices > Onboard Devices > Bluetooth