After reboot, bluetooth is active, but pairing no possible

A similar question was asked three years ago, with no answer.

After reboot of my Ubuntu 22.04, I always need to unplug-plug my ASUS USB-BT500 bluetooth stick so that keyboard and mouse can connect. Rarely a similar effect happens during a session (keyboard and mouse disconnect, and reconnect after unplug-plug).I have tried usbreset without success.

The following settings are equal after reboot (no connection) and unplug-plug (connected):

kjo@one:~$ lsusb Bus 001 Device 011: ID 0b05:190e ASUSTek Computer, Inc. ASUS USB-BT500kjo@one:~$ rfkill --output-all  ID TYPE      DEVICE TYPE-DESC   SOFT      HARD  1  bluetooth hci0   Bluetooth   unblocked unblocked

// Added on Nov 8:

1. The firmware does not seem to be the problem:

    kjo@one:~$ sudo dmesg|grep Bluetooth ... [   11.020767] Bluetooth: BNEP socket layer initialized [   18.756496] Bluetooth: hci0: RTL: HCI_OP_READ_LOCAL_VERSION failed (-110) [  302.409688] Bluetooth: hci0: RTL: examining hci_ver=0a hci_rev=000b lmp_ver=0a lmp_subver=8761 [  302.410650] Bluetooth: hci0: RTL: rom_version status=0 version=1 [  302.410652] Bluetooth: hci0: RTL: loading rtl_bt/rtl8761bu_fw.bin [  302.412865] Bluetooth: hci0: RTL: loading rtl_bt/rtl8761bu_config.bin [  302.413178] Bluetooth: hci0: RTL: cfg_sz 6, total sz 30210 [  302.561736] Bluetooth: hci0: RTL: fw version 0xdfc6d922

2. But the timeout at [ 18.756496] might give a hint?

// more observations:

• The fw is installed in the right places (since it is automatically loaded after bt-dongle is inserted)
• According to dmesg, the fw is not loaded at reboot, even if the dongle is connectd at boot-time. dmesg prints a timeout error HCI_OP_READ_LOCAL_VERSION failed (-110)
• The fw is loaded when the bt-dongle is inserted

// added Dec 23:// after reboot, stick is plugged in, bt does not work:

kjo@one:~$ hciconfig -ahci0:   Type: Primary  Bus: USBBD Address: 00:00:00:00:00:00  ACL MTU: 0:0  SCO MTU: 0:0DOWN RX bytes:0 acl:0 sco:0 events:0 errors:0TX bytes:0 acl:0 sco:0 commands:1 errors:1Features: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00Packet type: DM1 DH1 HV1 Link policy: Link mode: PERIPHERAL ACCEPT 

// after removing and inserting the stick, bt works now:

kjo@one:~$ hciconfig -ahci0:   Type: Primary  Bus: USBBD Address: 08:BF:B8:48:4D:B4  ACL MTU: 1021:6  SCO MTU: 255:12UP RUNNING PSCAN RX bytes:7328 acl:268 sco:0 events:302 errors:0TX bytes:35232 acl:91 sco:0 commands:200 errors:0Features: 0xff 0xff 0xff 0xfe 0xdb 0xfd 0x7b 0x87Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3 Link policy: RSWITCH HOLD SNIFF PARK Link mode: PERIPHERAL ACCEPT Name: 'one'Class: 0x6c0104Service Classes: Rendering, Capturing, Audio, TelephonyDevice Class: Computer, Desktop workstationHCI Version: 5.1 (0xa)  Revision: 0xdfc6LMP Version: 5.1 (0xa)  Subversion: 0xd922Manufacturer: Realtek Semiconductor Corporation (93)

// some more searching:// after reboot, stick plugged in, bt not available:

kjo@one:~$ sudo hciconfig hci0 upCan't init device hci0: Connection timed out (110)kjo@one:~$ sudo hciconfig hci0 resetCan't init device hci0: Connection timed out (110)kjo@one:~$ bluetoothctl listkjo@one:~$ bluetoothctlAgent registered[bluetooth]# pairable onNo default controller available[bluetooth]# list[bluetooth]# agent onAgent is already registered

// after removing and inserting the stick, keyboard and mouse connect:

[NEW] Controller 08:BF:B8:48:4D:B4 one [default][NEW] Device CB:01:A5:7C:EE:54 TrackPoint Keyboard II[NEW] Device D9:07:F2:94:63:8F ERGO M575[NEW] Device E4:F8:EF:53:B8:BA kjo[NEW] Device E0:9F:2A:18:7F:C8 Intuos BT S[CHG] Controller 08:BF:B8:48:4D:B4 Powered: yes[CHG] Controller 08:BF:B8:48:4D:B4 Alias: one...kjo@one:~$ bluetoothctl listController 08:BF:B8:48:4D:B4 one [default]

What can I do to avoid the unplug-plug?Thanks for help

Karl