Ubuntu
linux-firmware package

  1. Bug #1968604
  2. Comment #1

Comment 1 for bug 1968604

Revision history for this message
Bert RAM Aerts (bert.ram.aerts) wrote :

The firmware is NOT loaded correctly... the "bu" file is loaded instead of the "b"

I used to have Ubuntu 21.10 and my Bluetooth USB dongle was loading rtl8761b_fw.bin.
Last week I upgraded to Ubuntu 22.04 and since then I can not use my USB dongle, it connects my Sony headphones and immediately disconnects, connects, disconnects, ...
Using sudo dmesg | grep Bluetooth, I saw
[ 10.106036] Bluetooth: hci0: RTL: examining hci_ver=0a hci_rev=000b lmp_ver=0a lmp_subver=8761
[ 10.107035] Bluetooth: hci0: RTL: rom_version status=0 version=1
[ 10.107038] Bluetooth: hci0: RTL: loading rtl_bt/rtl8761bu_fw.bin
[ 10.108050] Bluetooth: hci0: RTL: loading rtl_bt/rtl8761bu_config.bin
[ 10.108170] Bluetooth: hci0: RTL: cfg_sz 6, total sz 27814
So kernel 5.15 loads different firmware rtl8761bu instead of rtl8761b used by kernel 5.13 in Ubuntu 21.10.
I guess this is a kernel bug.

As a workaround I made symbolic links and now my Bluetooth USB dongle works fine:
/lib/firmware/rtl_bt$ ls -al *8761*
lrwxrwxrwx 1 root root 19 Apr 10 06:32 rtl8761bu_config.bin -> rtl8761b_config.bin
lrwxrwxrwx 1 root root 15 Apr 10 06:32 rtl8761bu_fw.bin -> rtl8761b_fw.bin