Re: rtl_bt: RTL8852BU rom_version 3 has no matching in rtl8852bu_fw.bin

Hi Hilda,

I can confirm the exact same issue on my hardware, and I'd be glad to
take you up on the offer to test a pre-release firmware binary.

  Machine        : Lenovo IdeaPad
  BT controller  : 0bda:b853 (Realtek, USB), rom_version = 3
  Wi-Fi (same M.2): RTL8852BE, rtw89_8852be - works fine
  Driver         : btusb + btrtl
  linux-firmware : 20260622 (Fedora)
  Kernel         : 7.1.x

Same symptom as Deniz's report: rtl8852bu_fw.bin only carries eco 1/2,
the controller needs eco 4, so no patch is applied, BD_ADDR stays
00:00:00:00:00:00 and no controller is registered.

If you can share a candidate rtl8852bu_fw.bin with the eco 4 patch, I'll
install it and report back with dmesg / btmon and confirmation that the
controller enumerates and pairs. Happy to test as many revisions as
needed.

Thanks a lot for the quick turnaround and the fix!

Best regards,
Pavel