From: Zenm Chen <zenmchen@gmail.com>
To: linux-bluetooth@vger.kernel.org, max.chou@realtek.com,
hildawu@realtek.com
Cc: pkshih@realtek.com
Subject: bluetooth hci0: Direct firmware load for rtl_bt/rtl8761a_config.bin failed with error -2
Date: Thu, 30 Apr 2026 03:10:04 +0800 [thread overview]
Message-ID: <20260429191004.11965-1-zenmchen@gmail.com> (raw)
Hi,
Recently I got an RTL8812AEBT card which is a WiFi5 + BT4.0 device.
Bluetooth is working fine but I see the warning below in dmesg. It seems
the config file rtl_bt/rtl8761a_config.bin is missing, not sure if this
should be fixed or not.
$ dmesg
[ 171.900777] Bluetooth: Core ver 2.22
[ 171.900818] NET: Registered PF_BLUETOOTH protocol family
[ 171.900820] Bluetooth: HCI device and connection manager initialized
[ 171.900825] Bluetooth: HCI socket layer initialized
[ 171.900827] Bluetooth: L2CAP socket layer initialized
[ 171.900831] Bluetooth: SCO socket layer initialized
[ 171.934237] usbcore: registered new interface driver btusb
[ 171.941534] Bluetooth: hci0: RTL: examining hci_ver=06 hci_rev=000a lmp_ver=06 lmp_subver=8761
[ 171.943635] Bluetooth: hci0: RTL: rom_version status=0 version=3
[ 171.945657] Bluetooth: hci0: RTL: btrtl_initialize: key id 0
[ 171.945664] Bluetooth: hci0: RTL: loading rtl_bt/rtl8761a_fw.bin
[ 171.949630] Bluetooth: hci0: RTL: loading rtl_bt/rtl8761a_config.bin
[ 171.949697] bluetooth hci0: Direct firmware load for rtl_bt/rtl8761a_config.bin failed with error -2
[ 171.949712] Bluetooth: hci0: RTL: cfg_sz -2, total sz 22640
[ 172.020303] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[ 172.020309] Bluetooth: BNEP filters: protocol multicast
[ 172.020314] Bluetooth: BNEP socket layer initialized
[ 172.524780] Bluetooth: hci0: RTL: fw version 0x0e3e4380
[ 172.664330] Bluetooth: MGMT ver 1.22
[ 172.683252] NET: Registered PF_ALG protocol family
[ 172.744110] Bluetooth: RFCOMM TTY layer initialized
[ 172.744124] Bluetooth: RFCOMM socket layer initialized
[ 172.744136] Bluetooth: RFCOMM ver 1.11
$ sudo lsusb -v -d 0bda:b761
Bus 003 Device 004: ID 0bda:b761 Realtek Semiconductor Corp. Bluetooth Radio
Negotiated speed: Full Speed (12Mbps)
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.10
bDeviceClass 224 Wireless
bDeviceSubClass 1 Radio Frequency
bDeviceProtocol 1 Bluetooth
bMaxPacketSize0 64
idVendor 0x0bda Realtek Semiconductor Corp.
idProduct 0xb761 Bluetooth Radio
bcdDevice 2.00
iManufacturer 1 Realtek
iProduct 2 Bluetooth Radio
iSerial 3 00e04c000001
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 0x00b1
bNumInterfaces 2
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xe0
Self Powered
Remote Wakeup
MaxPower 500mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 3
bInterfaceClass 224 Wireless
bInterfaceSubClass 1 Radio Frequency
bInterfaceProtocol 1 Bluetooth
iInterface 4 Bluetooth Radio
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0010 1x 16 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 224 Wireless
bInterfaceSubClass 1 Radio Frequency
bInterfaceProtocol 1 Bluetooth
iInterface 4 Bluetooth Radio
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x03 EP 3 OUT
bmAttributes 1
Transfer Type Isochronous
Synch Type None
Usage Type Data
wMaxPacketSize 0x0000 1x 0 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x83 EP 3 IN
bmAttributes 1
Transfer Type Isochronous
Synch Type None
Usage Type Data
wMaxPacketSize 0x0000 1x 0 bytes
bInterval 1
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 1
bNumEndpoints 2
bInterfaceClass 224 Wireless
bInterfaceSubClass 1 Radio Frequency
bInterfaceProtocol 1 Bluetooth
iInterface 4 Bluetooth Radio
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x03 EP 3 OUT
bmAttributes 1
Transfer Type Isochronous
Synch Type None
Usage Type Data
wMaxPacketSize 0x0009 1x 9 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x83 EP 3 IN
bmAttributes 1
Transfer Type Isochronous
Synch Type None
Usage Type Data
wMaxPacketSize 0x0009 1x 9 bytes
bInterval 1
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 2
bNumEndpoints 2
bInterfaceClass 224 Wireless
bInterfaceSubClass 1 Radio Frequency
bInterfaceProtocol 1 Bluetooth
iInterface 4 Bluetooth Radio
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x03 EP 3 OUT
bmAttributes 1
Transfer Type Isochronous
Synch Type None
Usage Type Data
wMaxPacketSize 0x0011 1x 17 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x83 EP 3 IN
bmAttributes 1
Transfer Type Isochronous
Synch Type None
Usage Type Data
wMaxPacketSize 0x0011 1x 17 bytes
bInterval 1
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 3
bNumEndpoints 2
bInterfaceClass 224 Wireless
bInterfaceSubClass 1 Radio Frequency
bInterfaceProtocol 1 Bluetooth
iInterface 4 Bluetooth Radio
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x03 EP 3 OUT
bmAttributes 1
Transfer Type Isochronous
Synch Type None
Usage Type Data
wMaxPacketSize 0x0019 1x 25 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x83 EP 3 IN
bmAttributes 1
Transfer Type Isochronous
Synch Type None
Usage Type Data
wMaxPacketSize 0x0019 1x 25 bytes
bInterval 1
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 4
bNumEndpoints 2
bInterfaceClass 224 Wireless
bInterfaceSubClass 1 Radio Frequency
bInterfaceProtocol 1 Bluetooth
iInterface 4 Bluetooth Radio
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x03 EP 3 OUT
bmAttributes 1
Transfer Type Isochronous
Synch Type None
Usage Type Data
wMaxPacketSize 0x0021 1x 33 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x83 EP 3 IN
bmAttributes 1
Transfer Type Isochronous
Synch Type None
Usage Type Data
wMaxPacketSize 0x0021 1x 33 bytes
bInterval 1
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 5
bNumEndpoints 2
bInterfaceClass 224 Wireless
bInterfaceSubClass 1 Radio Frequency
bInterfaceProtocol 1 Bluetooth
iInterface 4 Bluetooth Radio
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x03 EP 3 OUT
bmAttributes 1
Transfer Type Isochronous
Synch Type None
Usage Type Data
wMaxPacketSize 0x0031 1x 49 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x83 EP 3 IN
bmAttributes 1
Transfer Type Isochronous
Synch Type None
Usage Type Data
wMaxPacketSize 0x0031 1x 49 bytes
bInterval 1
Binary Object Store Descriptor:
bLength 5
bDescriptorType 15
wTotalLength 0x000c
bNumDeviceCaps 1
USB 2.0 Extension Device Capability:
bLength 7
bDescriptorType 16
bDevCapabilityType 2
bmAttributes 0x00000002
HIRD Link Power Management (LPM) Supported
Device Status: 0x0001
Self Powered
$ sudo cat /sys/kernel/debug/usb/devices
T: Bus=03 Lev=01 Prnt=01 Port=04 Cnt=03 Dev#= 4 Spd=12 MxCh= 0
D: Ver= 2.10 Cls=e0(wlcon) Sub=01 Prot=01 MxPS=64 #Cfgs= 1
P: Vendor=0bda ProdID=b761 Rev= 2.00
S: Manufacturer=Realtek
S: Product=Bluetooth Radio
S: SerialNumber=00e04c000001
C:* #Ifs= 2 Cfg#= 1 Atr=e0 MxPwr=500mA
I:* If#= 0 Alt= 0 #EPs= 3 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb
E: Ad=81(I) Atr=03(Int.) MxPS= 16 Ivl=1ms
E: Ad=02(O) Atr=02(Bulk) MxPS= 64 Ivl=0ms
E: Ad=82(I) Atr=02(Bulk) MxPS= 64 Ivl=0ms
I:* If#= 1 Alt= 0 #EPs= 2 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb
E: Ad=03(O) Atr=01(Isoc) MxPS= 0 Ivl=1ms
E: Ad=83(I) Atr=01(Isoc) MxPS= 0 Ivl=1ms
I: If#= 1 Alt= 1 #EPs= 2 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb
E: Ad=03(O) Atr=01(Isoc) MxPS= 9 Ivl=1ms
E: Ad=83(I) Atr=01(Isoc) MxPS= 9 Ivl=1ms
I: If#= 1 Alt= 2 #EPs= 2 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb
E: Ad=03(O) Atr=01(Isoc) MxPS= 17 Ivl=1ms
E: Ad=83(I) Atr=01(Isoc) MxPS= 17 Ivl=1ms
I: If#= 1 Alt= 3 #EPs= 2 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb
E: Ad=03(O) Atr=01(Isoc) MxPS= 25 Ivl=1ms
E: Ad=83(I) Atr=01(Isoc) MxPS= 25 Ivl=1ms
I: If#= 1 Alt= 4 #EPs= 2 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb
E: Ad=03(O) Atr=01(Isoc) MxPS= 33 Ivl=1ms
E: Ad=83(I) Atr=01(Isoc) MxPS= 33 Ivl=1ms
I: If#= 1 Alt= 5 #EPs= 2 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb
E: Ad=03(O) Atr=01(Isoc) MxPS= 49 Ivl=1ms
E: Ad=83(I) Atr=01(Isoc) MxPS= 49 Ivl=1ms
next reply other threads:[~2026-04-29 19:10 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-29 19:10 Zenm Chen [this message]
2026-04-30 2:22 ` bluetooth hci0: Direct firmware load for rtl_bt/rtl8761a_config.bin failed with error -2 Max Chou
2026-05-05 7:25 ` Zenm Chen
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