operating-system: Missing firmware file rtl_bt/rtl8761b_fw.bin

Not sure if I should log a bug/enhancement as well, seem to be having the same issue. I see the commit is completed but still in Dev. (btw thanks @agners)

[16263.319768] usb 1-1.4: USB disconnect, device number 4
[16642.754635] usb 1-1.2: new full-speed USB device number 5 using dwc_otg
[16642.887871] usb 1-1.2: New USB device found, idVendor=0bda, idProduct=8771, bcdDevice= 2.00
[16642.887899] usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[16642.887919] usb 1-1.2: Product: Bluetooth Radio
[16642.887936] usb 1-1.2: Manufacturer: Realtek
[16642.887953] usb 1-1.2: SerialNumber: 00E04C239987
[16642.907465] Bluetooth: hci0: RTL: examining hci_ver=0a hci_rev=000b lmp_ver=0a lmp_subver=8761
[16642.909456] Bluetooth: hci0: RTL: rom_version status=0 version=1
[16642.909486] Bluetooth: hci0: RTL: loading rtl_bt/rtl8761b_fw.bin
[16642.923271] bluetooth hci0: Direct firmware load for rtl_bt/rtl8761b_fw.bin failed with error -2
[16642.923306] Bluetooth: hci0: RTL: firmware file rtl_bt/rtl8761b_fw.bin not found

_Originally posted by @kelos-01 in https://github.com/home-assistant/operating-system/issues/1273#issuecomment-809614902_