armbian-firmware: add rtl8761bu Bluetooth firmware

[hanscees]

Creating a bug report/issue

• I have searched the existing open and closed issues

found a closed ticket in 2024, but bug is still there.

Required Information

G_DIETPI_VERSION_CORE=9
G_DIETPI_VERSION_SUB=20
G_DIETPI_VERSION_RC=1
G_GITBRANCH='master'
G_GITOWNER='MichaIng'

Additional Information (if applicable)

• Was the software title installed freshly or updated/migrated?
  yes

• Can this issue be replicated on a fresh installation of DietPi?
  yes

• Distro version | echo $G_DISTRO_NAME $G_RASPBIAN
  trixy

• Kernel version | uname -a
Linux DietPi 6.12.58-current-sunxi64 #1 SMP Thu Nov 13 20:34:41 UTC 2025 aarch64 GNU/Linux

• SBC model | echo $G_HW_MODEL_NAME or (EG: RPi3)
  NanoPi NEO2 (aarch64)

Steps to reproduce

1. plug usb bluetooth dongle in
   lsusb
   Bus 004 Device 002: ID 0bda:a728 Realtek Semiconductor Corp. Bluetooth 5.4 Radio

dmesg

[   11.970101] Bluetooth: Core ver 2.22
[   11.970308] NET: Registered PF_BLUETOOTH protocol family
[   11.970318] Bluetooth: HCI device and connection manager initialized
[   11.970351] Bluetooth: HCI socket layer initialized
[   11.970366] Bluetooth: L2CAP socket layer initialized
[   11.970398] Bluetooth: SCO socket layer initialized
[   12.010613] usbcore: registered new interface driver btusb
[   12.015696] Bluetooth: hci0: RTL: examining hci_ver=0a hci_rev=000b lmp_ver=0a lmp_subver=8761
[   12.017697] Bluetooth: hci0: RTL: rom_version status=0 version=1
[   12.017756] Bluetooth: hci0: RTL: loading rtl_bt/rtl8761bu_fw.bin
[   12.032886] Bluetooth: hci0: RTL: loading rtl_bt/rtl8761bu_config.bin
[   12.037055] Bluetooth: hci0: RTL: cfg_sz 6, total sz 17782
[   12.210711] Bluetooth: hci0: RTL: fw version 0x09002b09
[   12.349854] dwmac-sun8i 1c30000.ethernet eth0: Register MEM_TYPE_PAGE_POOL RxQ-0
[   12.353181] dwmac-sun8i 1c30000.ethernet eth0: PHY [mdio_mux-0.2:07] driver [RTL8211E Gigabit Ethernet] (irq=POLL)
[   12.353261] dwmac-sun8i 1c30000.ethernet eth0: No Safety Features support found
[   12.353281] dwmac-sun8i 1c30000.ethernet eth0: No MAC Management Counters available
[   12.353296] dwmac-sun8i 1c30000.ethernet eth0: PTP not supported by HW
[   12.353967] dwmac-sun8i 1c30000.ethernet eth0: configuring for phy/rgmii-id link mode
[   12.623276] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[   12.623312] Bluetooth: BNEP filters: protocol multicast
[   12.623342] Bluetooth: BNEP socket layer initialized
[   12.633893] Bluetooth: MGMT ver 1.23
[   12.654067] NET: Registered PF_ALG protocol family
[   12.740191] Bluetooth: RFCOMM TTY layer initialized
[   12.740255] Bluetooth: RFCOMM socket layer initialized
[   12.740286] Bluetooth: RFCOMM ver 1.11

2. The firmware seemed to be missing, so I downloaded it
   as in this ticket
   https://dietpi.com/forum/t/firmware-rtl8761bu-is-missing-from-armbian-firmware-package/21502

wget https://github.com/Elif-dot/RTL8761BU/raw/refs/heads/master/8761BU/rtl8761bu_fw 
wget https://github.com/Elif-dot/RTL8761BU/raw/refs/heads/master/8761BU/rtl8761bu_config
mv rtl8761bu_fw rtl8761bu_fw.bin
mv rtl8761bu_config rtl8761bu_config.bin
cp rtl8761bu_fw.bin /usr/lib/firmware/rtl_bt/
cp rtl8761bu_config.bin /usr/lib/firmware/rtl_bt/
chmod 664 /usr/lib/firmware/rtl_bt/rtl8761bu_fw.bin
chmod 664 /usr/lib/firmware/rtl_bt/rtl8761bu_config.bin

after that all worked

Expected behaviour

dongle should be recognized and usable directly

Actual behaviour

hciconfig shows no mac address