I have been trying to use CSR 4.0 BLE DONGLE (Cambridge Silicon Radio, Ltd Bluetooth Dongle) with Bananapi M4 using raspbian image.
lsusb:
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 004: ID 0bda:c820 Realtek Semiconductor Corp.
Bus 001 Device 003: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)
Bus 001 Device 002: ID 1a40:0201 Terminus Technology Inc. FE 2.1 7-port Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
hcitool dev: Devices: hci0 54:EF:33:62:50:13
Only the built-in bluetooth appears. But the bt dongle does not seem to working. Also tried with ubuntu mate and ubuntu server images, but still not usable. the dongle is working fine on original raspberry pi 4 and B3+
kindly help