happened for me too, i solved it by installing mission control and nx-btred from hb appstore, after that it worked for me on the latest atmosphere with mesosphere kernel + latest firmware.I tried this on the latest firmware.
When i copy the nx-bted-0.9.3\atmosphere\contents\0100000000000081
It causes system boot error.
Error Desc: std::abort() called (0xffe)
When i remove the above folder the switch boots normally, I have mission controlled installed, Have not confirgured anything just installed mission control and then nx-bted-0.9.3 and i get boot error.
After i remove the above folder and boot into the switch, when i open the app in the hbmenu (Bluetooth Pairing)
All i get is: BtPariningManager Initalize F601
and nothing else. pressing any of the buttons does nothing