Bluetooth scan doesn't detect any device on Ubuntu 21.10

I have just bought a Tp-link bluetooth 5.0 usb adapter (UB500), I've checked and its chip is Realtek RTL8761B. It works just fine on Windows 10, but I'm having problems on Ubuntu. I'm running Ubuntu 21.10 and I've just upgraded to the latest stable kernel version: 5.14.14. Before upgrading I tried this solution but with no success:

I've tried almost everything I've found online, but most of the solutions don't apply because there is no evident problem: the adapter seems to be correctly installed and properly working, however scanning does not pick up any bluetooth device. I've tried two headsets (that I know are properly working) and my phone, with no success. When performing a scan on my phone, the computer doesn't show up, even if I've set it to visible.

I can't figure out what the problem is.

 dmesg |grep -i bluetooth [ 3.596913] Bluetooth: Core ver 2.22 [ 3.596935] NET: Registered PF_BLUETOOTH protocol family [ 3.596936] Bluetooth: HCI device and connection manager initialized [ 3.596939] Bluetooth: HCI socket layer initialized [ 3.596941] Bluetooth: L2CAP socket layer initialized [ 3.596945] Bluetooth: SCO socket layer initialized [ 93.519895] Bluetooth: BNEP (Ethernet Emulation) ver 1.3 [ 93.519899] Bluetooth: BNEP filters: protocol multicast [ 93.519903] Bluetooth: BNEP socket layer initialized [ 144.060814] Bluetooth: RFCOMM TTY layer initialized [ 144.060821] Bluetooth: RFCOMM socket layer initialized [ 144.060825] Bluetooth: RFCOMM ver 1.11

 hciconfig -a hci0: Type: Primary Bus: USB BD Address: E8:48:B8:C8:20:00 ACL MTU: 1021:6 SCO MTU: 255:12 UP RUNNING RX bytes:4264 acl:0 sco:0 events:560 errors:0 TX bytes:9000 acl:0 sco:0 commands:490 errors:0 Features: 0xff 0xff 0xff 0xfe 0xdb 0xfd 0x7b 0x87 Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3 Link policy: RSWITCH HOLD SNIFF PARK Link mode: SLAVE ACCEPT Name: 'gaia-ubuntu-desktop' Class: 0x7c0104 Service Classes: Rendering, Capturing, Object Transfer, Audio, Telephony Device Class: Computer, Desktop workstation HCI Version: 5.1 (0xa) Revision: 0xb LMP Version: 5.1 (0xa) Subversion: 0x8761 Manufacturer: Realtek Semiconductor Corporation (93)

 rfkill list 0: hci0: Bluetooth Soft blocked: no Hard blocked: no

 lsusb Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 003 Device 004: ID 046d:0826 Logitech, Inc. HD Webcam C525 Bus 003 Device 003: ID 04b8:013d Seiko Epson Corp. Epson Perfection V39 Bus 003 Device 002: ID 0c76:2068 JMTek, LLC. USB MIC-SG01 Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 003: ID 2357:0604 TP-Link TP%Link UB500 Adapter Bus 001 Device 002: ID 062a:3633 MosArt Semiconductor Corp. Full-Speed Mouse Bus 001 Device 004: ID 145f:0176 Trust Isla Keyboard Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

usb-devices | awk '/0604/' RS=
T: Bus=01 Lev=01 Prnt=01 Port=07 Cnt=03 Dev#= 3 Spd=12 MxCh= 0
D: Ver= 1.10 Cls=e0(wlcon) Sub=01 Prot=01 MxPS=64 #Cfgs= 1
P: Vendor=2357 ProdID=0604 Rev=02.00
S: Manufacturer=
S: Product=TP%Link UB500 Adapter
S: SerialNumber=E848B8C82000
C: #Ifs= 2 Cfg#= 1 Atr=e0 MxPwr=500mA
I: If#=0x0 Alt= 0 #EPs= 3 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb
I: If#=0x1 Alt= 0 #EPs= 2 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb

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4 Answers

I have faced the same issue with the Tp-Link UB500 adapter and I could solve this problem as suggested by Pilot6. Follow the steps below. Thanks to Pilot6.

Step 1: Download and extract Linux kernel source file.

wget
tar xpvf linux-5.11.tar.xz

Be sure to use kernel version according to your system (can be checked with uname -r)

Step 2: Edit btusb.c

cd linux-5.11/drivers/bluetooth
gedit btusb.c

add the following

/* Tp-Link UB500 */
{ USB_DEVICE(0x2357, 0x0604), .driver_info = BTUSB_REALTEK },

Under the section "static const struct usb_device_id blacklist_table[]". After /* Silicon Wave based devices */.

Step 3: Edit hci_ldisc.c

(may not be needed for some versions of kernel)

Replace

static ssize_t hci_uart_tty_read(struct tty_struct *tty, struct file *file, unsigned char __user *buf, size_t nr)

to

static ssize_t hci_uart_tty_read(struct tty_struct *tty, struct file *file, unsigned char __user *buf, size_t nr, void **cookie, unsigned long offset)

Step 4: Compile modules

make -C /lib/modules/$(uname -r)/build M=$(pwd) clean
cp /usr/src/linux-headers-$(uname -r)/.config ./
cp /usr/src/linux-headers-$(uname -r)/Module.symvers Module.symvers
make -C /lib/modules/$(uname -r)/build M=$(pwd) modules
sudo cp btusb.ko /lib/modules/$(uname -r)/kernel/drivers/bluetooth

If you have secure boot, it's also needed to sign the module, search for "How to sign things for Secure Boot".

Step 5: Repalce the old module

sudo cp btusb.ko /lib/modules/$(uname -r)/kernel/drivers/bluetooth

Step 6: Load new btusb

sudo modprobe -r btusb
sudo modprobe -v btusb

It's working for me!

12

If the device is RTL8761B, then a patch to btusb.c kernel code is needed, adding this:

 /* Tp-Link UB500 */
{ USB_DEVICE(0x2357, 0x0604), .driver_info = BTUSB_REALTEK },

The problem is that nobody has added this device to Linux kernel yet. The chip seems to be supported, but the Tp-Link id is not there.

I suggest reporting this to Launchpad. Boot with an Ubuntu kernel and run in a terminal

ubuntu-bug linux

That will create a bug report.

10

I followed the steps in @gauthsree answer and the system stopped detecting the adapter.

Then (after a lot of searching and reading) i ran lsusb; dmesg | egrep -i 'blue|firm' and got this:

RTL: firmware file rtl_bt/rtl8761b_fw.bin not found

So, i downloaded the file and placed in: /lib/firmware/rtl_bt/

Then, reboot the system and finally works!

I followed this tutorial: Bluetooth 5.0 chipset Realtek RTL8761B to download and copy the firmware.

My system:

• OS: Ubuntu 20.04.1
• Kernel: 5.11.0-46-generic

Hope this help!

2

Here is a script that does all the steps of Aeolun.

Also Driver is downloaded and copied, like Laion described.

(I am just learning to bash script and I tried this and thougth I share.)

#!/bin/bash
# Initialization
FIX_UB_500_BT_Stick () {
echo -e "This Script is intended to fix the not working BT Stick UB 500 by TP-Link"
echo -e ""
echo -e "As descrbed in "
echo -e ""
echo -e "This scripts guides you through all necessary steps. However, please take care. This can break your system, or at least break your bluetooth."
echo -e ""
echo -e "\033[33mStep 1: Download and extract Linux kernel source file."
echo -e "\033[0m"
echo -e ""
echo -e "Your Kernel-Version: "
version=$(uname -r)
echo $version
echo -e "If not 5.13, change script and restart! (Just search and replace 5.13 with your Version, as long as it is a 5.x)"
read -n 1 -p "Do you want to continue? [y/n]" start if [ "$start" = "y" ] ; then cd /home/max/ mkdir FIX_UB_500_BT_Stick cd FIX_UB_500_BT_Stick wget tar xpvf linux-5.13.tar.xz echo -e "\033[33mDownload location and files:" echo -e "\033[0m" pwd ls echo -e "\033[33mLocation of files to be changed:" echo -e "\033[0m" cd linux-5.13/drivers/bluetooth pwd echo -e "\033[33mStep 2: Edit btusb.c" echo -e "\033[31m" echo "Add:" echo -e "\033[0m" echo "/* Tp-Link UB500 */" echo "{ USB_DEVICE(0x2357, 0x0604), .driver_info = BTUSB_REALTEK }," echo -e "\033[33m" echo "Under the section" echo -e "\033[0m" echo "static const struct usb_device_id blacklist_table[]" echo -e "\033[33m" echo "After" echo -e "\033[0m" echo "/* Silicon Wave based devices */" echo -e "\033[33m" echo "in btusb.c" echo "" echo "It should look something like this:" echo -e "\033[0m" echo "/* Silicon Wave based devices */" echo "{ USB_DEVICE(0x0c10, 0x0000), .driver_info = BTUSB_SWAVE }," echo "/* Tp-Link UB500 */" echo "{ USB_DEVICE(0x2357, 0x0604), .driver_info = BTUSB_REALTEK }, " echo "{ }/* Terminating entry */" echo "" echo -e "\033[31m Safe and close KWrite." sleep 5 kwrite btusb.c read -n 1 -p "Did you change the file and want to continue? [y/n]" filechange1 if [ "$filechange1" = "y" ]; then echo -e "\033[33m" echo "Ok, continuing." echo -e "\033[0m" elif [ "$filechange1" = "n" ];then sudo rm -r /home/max/FIX_UB_500_BT_Stick exit else echo -e "\033[31mDid you change the file and want to continue? [y/n]; Press ctrl+c to abort." echo -e "\033[0m" read -n 1 fi echo -e "\033[33mStep 3: Edit hci_ldisc.c" echo -e "\033[0m" echo -e "" File="hci_ldisc.c" if grep -q "void **cookie, unsigned long offset)" "$File"; then echo -e "\033[33mStep not necessary. File already correct." echo -e "\033[0m" else echo -e "\033[33mChange:" echo -e "\033[0m" echo "static ssize_t hci_uart_tty_read(struct tty_struct *tty, struct file *file," echo " unsigned char __user *buf, size_t nr)" echo "" echo -e "\033[33minto" echo -e "\033[0m" echo "static ssize_t hci_uart_tty_read(struct tty_struct *tty, struct file *file," echo " unsigned char __user *buf, size_t nr, " echo " void **cookie, unsigned long offset) " echo -e "\033[33m" echo "in hci_ldisc.c" echo "" echo "Safe and Close KWrite. (This step might not be necessary for some versions)" sleep 5 kwrite hci_ldisc.c read -n 1 -p "Did you change the file and want to continue? [y/n]" filechange2 if [ "$filechange2" = "y" ]; then echo -e "\033[33m" echo "Ok, continuing." echo -e "\033[0m" elif [ "$filechange2" = "n" ];then sudo rm -r /home/max/FIX_UB_500_BT_Stick exit else echo -e "\033[31mDid you change the file and want to continue? [y/n];" read -n 1 fi fi echo -e "\033[33mStep 4: Compile modules." echo -e "\033[0m" make -C /lib/modules/$(uname -r)/build M=$(pwd) clean echo -e "\033[33mMake 1 done." echo -e "\033[0m" cp /usr/src/linux-headers-$(uname -r)/.config ./ cp /usr/src/linux-headers-$(uname -r)/Module.symvers Module.symvers make -C /lib/modules/$(uname -r)/build M=$(pwd) modules echo -e "\033[33mMake 2 done." echo -e "\033[33mStep 5: Replace the old module." echo -e "\033[0m" sudo cp btusb.ko /lib/modules/$(uname -r)/kernel/drivers/bluetooth echo -e "\033[33mCopied to current Kernel" echo -e "" echo -e "\033[33mStep 6: Load new btusb." echo -e "\033[0m" sudo modprobe -r btusb sudo modprobe -v btusb echo -e "\033[33mModprobe done" echo -e "\033[0m" if [[ ! -f "/lib/firmware/rtl_bt/rtl8761b_fw.bin" ]] then echo -e "\033[33mStep 7: Download Firmware for UB500 from Realteks GIT." read -n 1 -p "The FW for the UB500 BT-Dongle is not present in /lib/firmware/rtl_bt/. /n Do you wish to download the file from Realteks Git and copy it to your system? [y/n]" FW_Install if [ "$FW_Install" = "y" ]; then echo -e "\033[33m" echo "Ok, continuing." echo -e "\033[0m" cd /home/max/FIX_UB_500_BT_Stick mkdir FW cd FW wget sudo cp /home/max/FIX_UB_500_BT_Stick/FW/rtl8761b_fw /lib/firmware/rtl_bt/rtl8761b_fw.bin if [[ -f "/lib/firmware/rtl_bt/rtl8761b_fw.bin" ]]; then echo -e "\033[33mFW was successfully copied. Reboot and try your bluetooth stick. It should work now." else echo -e "\033[33mSomething went wrong.You will have to download the FW yourself and place it in the folder /lib/firmware/rtl_bt/ with the name rtl8761b_fw.bin /n You'll find the file in this Repo: /n If you placed the file there, reboot and your UB500 should work now." fi elif [ "$fFW_Install" = "n" ];then sudo rm -r /home/max/FIX_UB_500_BT_Stick echo -e "\033[33mFW was not downloaded. You will have to download the FW yourself and place it in the folder /lib/firmware/rtl_bt/ with the name rtl8761b_fw.bin /n You'll find the file in this Repo: /n If you placed the file there, reboot and your UB500 should work now." echo -e "\033[0m" exit else echo -e "\033[31mDownload the FW? [y/n];" read -n 1 fi else echo -e "\033[33mIt looks like, /lib/firmware/rtl_bt/rtl8761b_fw.bin already exists. No further steps needed. Reboot and try your UB500 BT-Stick." fi sudo rm -r /home/max/FIX_UB_500_BT_Stick echo -e "\033[33mDeleted downloaded files and dircetory /home/max/FIX_UB_500_BT_Stick" echo -e "\033[0m" elif [ "$start" = "n" ];then sudo rm -r /home/max/FIX_UB_500_BT_Stick exit else echo -e "\033[33mYou have entered an invallid selection!" echo -e "\033[33mPlease try again!" echo -e "" echo -e "\033[31mPress any key to continue..." read -n 1 fi }
FIX_UB_500_BT_Stick

In Step 3 sadly the check in hci_ldisc.c does not work. So you have to check manually.

It uses kwrite as texteditor.

Do not run script as sudo. Wait for it to ask you for sudo.

If you are like myself new to all of it:

For this to work, create a textfile but use extension .sh not .txt

Copy all the code in it and safe.

In your directory open a terminal.

chmod a+x YOURFILE.sh

bash YOURFILE.sh

Follow instructions precisely.

I edited my answer quite a lot, so it is more helpfull.

6