Bluetooth support missing for rev 2

ScoreABSM · June 21

Context: new Banana Pi M4 zero (rev 2) is using Wifi/BT over SDIO, which requires an sdio overlay. Thanks to Armbian team for providing it. Editing armbianEnv.txt to add "overlays=bananapi-m4-sdio-wifi-bt" did the trick for Wifi but BT is still not available (neither in standard or rolling builds)...

@c0rnelius I know you tried to figure out why, I'm missing technical knowledge to help... Digging the Internet I saw similar bluetooth issue for radxa zero 3w with aic8800, resolved using hciattach / hci up, but needing an available /dev/ttyS1 (UART1) we are missing here... Do you know why? Could it be the problem for banana pi m4 zero and if yes could an overlay activate it?

Denis

c0rnelius · June 21

Here is a more vanilla build of the kernel.

patrick@bananapim4zero:~$ ls /dev/ttyS*
/dev/ttyS0  /dev/ttyS3  /dev/ttyS5  /dev/ttyS7
/dev/ttyS2  /dev/ttyS4  /dev/ttyS6
patrick@bananapim4zero:~$ sudo rfkill
ID TYPE      DEVICE      SOFT      HARD
 0 bluetooth hci0   unblocked unblocked
 1 wlan      phy0   unblocked unblocked
patrick@bananapim4zero:~$ bluetoothctl
hci0 new_settings: powered bondable ssp br/edr le secure-conn 
Agent registered
[CHG] Controller AC:6A:A3:3B:D9:D6 Pairable: yes
[bluetoothctl]> exit
patrick@bananapim4zero:~$ uname -a
Linux bananapim4zero 6.12.32 #1 SMP Sat Jun  7 17:23:51 EDT 2025 aarch64 GNU/Linux
patrick@bananapim4zero:~$ dmesg | grep brcm
[    9.007064] brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac43455-sdio for chip BCM4345/6
[    9.007614] usbcore: registered new interface driver brcmfmac
[    9.303238] brcmfmac: brcmf_c_process_txcap_blob: no txcap_blob available (err=-2)
[    9.303576] brcmfmac: brcmf_c_preinit_dcmds: Firmware: BCM4345/6 wl0: Aug 29 2023 01:47:08 version 7.45.265 (28bca26 CY) FWID 01-b677b91b
[    9.430799] Bluetooth: hci0: BCM4345C0 'brcm/BCM4345C0.sinovoip,bpi-m4-zero.hcd' Patch

As you can see the Bluetooth works fine.

If I add these two patches it breaks bluetooth on this kernel build.

drv-rtc-sun6i-support-RTCs-without-external-LOSCs.patch

drv-rtc-sun6i-Add-Allwinner-H616-support.patch

I'm still investigating in my spare time, but I'm not 100% on anything. Could be I need to take another approach to the bluetooth node in Armbian? So this is where am at. If anyone has any thoughts I'm all ears.