Bluetooth doesn't appear after boot very often in Orange Pi 2W

sminder · June 5

I've got Orange Pi 2W board and installed Debian 12 Home Assistant image to it (image link). There is a huge problem with it. Very often there is no bluetooth module appeared in system. I need to reboot system for 10-15 timer to make it work. What can be a reason?

I attached 2 boot logs (with good BT appears and no BT appears), I hope it will help to find out the issue.

boot_log_bt_good_02.zip

boot_log_bt_bad_02.zip

IBV · June 9

Hi,

without owning this board, chatgpt is pointing out to an initialisation issue of the bluetooth system caused by the GPIO pin not being correctly handled at boot.

 [    6.024062] WCN: marlin chip en dummy pull up -- need manually set GPIO

The correct solution would be to handle the init in the dtb file, but you can try the following systemd initialisation as a workaround to see if it works.

Create (as root) the following service file /etc/systemd/system/bt-gpio.service with the contents:

[Unit]
Description=Enable GPIO for Bluetooth chip
Before=bluetooth.service

[Service]
Type=oneshot
ExecStart=/bin/sh -c 'echo 225 > /sys/class/gpio/export || true; echo out > /sys/class/gpio/gpio225/direction; echo 1 > /sys/class/gpio/gpio225/value'

[Install]
WantedBy=multi-user.target

Then enable it (as root):

systemctl daemon-reexec
systemctl daemon-reload
systemctl enable bt-gpio.service

Reboot and check if the bluetooth starts correctly. Post the boot log if it does not.

Michael Robinson · June 9

Also Check your PSU if the problem is intermittent.

sminder · June 10

Thank you for the suggestion. Unfortunately, it didn't help. Here is a boot log after your fix:

bt_boot_fail_after_fix.txt

IBV · June 10

I did not see the bt-gpio service starting on boot.

Can you post the status ?

On 6/9/2025 at 8:28 AM, IBV said:
systemctl status bt-gpio.service

sminder · June 11

user@orangepizero2w:~$ systemctl status bt-gpio.service
× bt-gpio.service - Enable GPIO for Bluetooth chip
     Loaded: loaded (/etc/systemd/system/bt-gpio.service; enabled; preset: enabled)
     Active: failed (Result: exit-code) since Tue 2025-06-10 23:18:23 +03; 11h ago
    Process: 489 ExecStart=/bin/sh -c echo 225 > /sys/class/gpio/export || true; echo out > /sys/class/gpio/gpio225/direction; echo 1 > /sys/class/gpio/gpio225/value (code=exited, status=2)
   Main PID: 489 (code=exited, status=2)
        CPU: 5ms

jun 10 23:18:23 orangepizero2w systemd[1]: Starting bt-gpio.service - Enable GPIO for Bluetooth chip...
jun 10 23:18:23 orangepizero2w sh[489]: /bin/sh: 1: echo: echo: I/O error
jun 10 23:18:23 orangepizero2w sh[489]: /bin/sh: 1: cannot create /sys/class/gpio/gpio225/direction: Directory nonexistent
jun 10 23:18:23 orangepizero2w sh[489]: /bin/sh: 1: cannot create /sys/class/gpio/gpio225/value: Directory nonexistent
jun 10 23:18:23 orangepizero2w systemd[1]: bt-gpio.service: Main process exited, code=exited, status=2/INVALIDARGUMENT
jun 10 23:18:23 orangepizero2w systemd[1]: bt-gpio.service: Failed with result 'exit-code'.
jun 10 23:18:23 orangepizero2w systemd[1]: Failed to start bt-gpio.service - Enable GPIO for Bluetooth chip.

Also I attached boot log which is connected to that "systemctl status bt-gpio.service" command.

bt_fail_boot_log_3.txt

When the board was boot correctly (BT is working fine) the output looks the same:

user@orangepizero2w:~$ systemctl status bt-gpio.service
× bt-gpio.service - Enable GPIO for Bluetooth chip
     Loaded: loaded (/etc/systemd/system/bt-gpio.service; enabled; preset: enabled)
     Active: failed (Result: exit-code) since Wed 2025-06-11 11:04:21 +03; 1min 30s ago
    Process: 492 ExecStart=/bin/sh -c echo 225 > /sys/class/gpio/export || true; echo out > /sys/class/gpio/gpio225/direction; echo 1 > /sys/class/gpio/gpio225/value (code=exited, status=2)
   Main PID: 492 (code=exited, status=2)
        CPU: 5ms

jun 11 11:04:21 orangepizero2w systemd[1]: Starting bt-gpio.service - Enable GPIO for Bluetooth chip...
jun 11 11:04:21 orangepizero2w sh[492]: /bin/sh: 1: echo: echo: I/O error
jun 11 11:04:21 orangepizero2w sh[492]: /bin/sh: 1: cannot create /sys/class/gpio/gpio225/direction: Directory nonexistent
jun 11 11:04:21 orangepizero2w sh[492]: /bin/sh: 1: cannot create /sys/class/gpio/gpio225/value: Directory nonexistent
jun 11 11:04:21 orangepizero2w systemd[1]: bt-gpio.service: Main process exited, code=exited, status=2/INVALIDARGUMENT
jun 11 11:04:21 orangepizero2w systemd[1]: bt-gpio.service: Failed with result 'exit-code'.
jun 11 11:04:21 orangepizero2w systemd[1]: Failed to start bt-gpio.service - Enable GPIO for Bluetooth chip.

IBV · June 11

Can you post your /boot/armbianEnv.txt ?

sminder · June 11

Sure.

armbianEnv.txt

IBV · June 11

sudo armbian-config

Are you able to see the below overlays ? If yes, activate them.

System → Hardware/Kernel → Activate UART0, UART1, BT overlays

sminder · June 11

I don't see such interfaces. Could you point me if one of these are suitable?

armbian_002.png.663ca5abfc5d7cf7eb5f87bde5f978b5.png

IBV · June 11

Difficult to see like this, better list the overlay directory:

ls /boot/dtb/overlays

sminder · June 11

ls: unable to get access to '/boot/dtb/overlays': No such file or directory.

Despite this, I attached full tree of "boot" directory.

boot_dir_content.txt

Edited June 11 by sminder

IBV · June 12

Ok,

if you want we can try one more thing. According to AI, the correct way to always enable the bluetooth is to do it via a custom overlay, which is not done.

First, remove the bt-gpio.service, it does not help:

sudo sytemctl disable bt-gpio.service
sudo rm /etc/systemd/system/bt-gpio.service
sudo systemctl daemon-reload

Then, create the custom overlay file /boot/overlay-user/bt_enable_ph1.dts with the following content:

/dts-v1/;
/plugin/;

&pio {
    bt_en_pin: bt_en_pin {
        pins = "PH1";
        function = "gpio_out";
        bias-pull-up;
        output-high;
    };
};

&uart0 {
    pinctrl-names = "default";
    pinctrl-0 = <&uart0_pins>;
    status = "okay";
};

&wcn_bt {
    compatible = "wcn,bt";
    uart = <&uart0>;
    enable-gpios = <&pio 7 1 GPIO_ACTIVE_HIGH>;  // PH1 = GPIO 225
    status = "okay";
};

Then we can try to compile and install it:

sudo armbian-add-overlay /boot/overlay-user/bt_enable_ph1.dts

Then activate it in /boot/armbianEnv.txt, add the following line:

user_overlays=bt_enable_ph1

If all works well try to reboot and see what happens.

sminder · June 12

sudo armbian-add-overlay /boot/overlay-user/bt_enable_ph1.dts
Compiling the overlay
Error: /boot/overlay-user/bt_enable_ph1.dts:22.30-31 syntax error
FATAL ERROR: Unable to parse input tree
Error compiling the overlay

Unfortunately, I didn't understand what the error is.

IBV · June 12

Ok, replace the contents of the dts file with this:

/dts-v1/;
/plugin/;

/ {
    fragment@0 {
        target = <&pio>;
        __overlay__ {
            bt_enable_pin: bt_enable_pin {
                pins = "PH1";
                function = "gpio_out";
                bias-pull-up;
                output-high;
            };
        };
    };
};

And try again the steps

sminder · June 12

That was successful. Unfortunately, the fail rate not too much better than as I added new service: one boot was good, one was bad. Here is a log of the fail boot.

bt_boot_fail_after_new_devicetree.txt

IBV · June 12

Ok,

create a new dts /boot/overlay-user/bt_enable_full.dts

/dts-v1/;
/plugin/;

&pio {
    bt_en_pin: bt_en_pin {
        pins = "PH1";
        function = "gpio_out";
        bias-pull-up;
        output-high;
    };

    bt_wake_pin: bt_wake_pin {
        pins = "PH0";
        function = "gpio_in";
        bias-pull-up;
    };
};

&{/soc} {
    wcn_bt: wcn_bt@0 {
        compatible = "wcn,bt";
        status = "okay";
        enable-gpios = <&pio 7 1 GPIO_ACTIVE_HIGH>; // PH1 = GPIO225
        wake-gpios = <&pio 7 0 GPIO_ACTIVE_HIGH>;   // PH0 = GPIO224 (if connected)
    };
};

And compile it:

sudo armbian-add-overlay /boot/overlay-user/bt_enable_full.dts

Then enable it in /boot/armbianEnv.txt

user_overlays=bt_enable_full

See if there's an improvement on boot.

sminder · June 12

sudo armbian-add-overlay /boot/overlay-user/bt_enable_full.dts
Compiling the overlay
Error: /boot/overlay-user/bt_enable_full.dts:23.34-35 syntax error
FATAL ERROR: Unable to parse input tree
Error compiling the overlay

Ok, I guess the problem was in "GPIO_ACTIVE_HIGH" macros. So I changed them to "1". File has compiled and I begun to test the board.

Two times in row the board booted ok, but next time BT has failed.

IBV · June 12

Interesting, pls post the failed boot.

sminder · June 12

bt_boot_fail_04.txt

IBV · June 12

Ok, try with this dts file /boot/overlay-user/bt_enable_clean.dts

/dts-v1/;
/plugin/;

&pio {
    bt_en_pin: bt_en_pin {
        pins = "PH1";                  // GPIO225
        function = "gpio_out";
        bias-pull-up;
        drive-strength = <20>;
        output-high;
    };
};

Compile it:

sudo armbian-add-overlay /boot/overlay-user/bt_enable_clean.dts

and enable it in /boot/armbianEnv.txt

user_overlays=bt_enable_clean

Then see if better on reboot.

sminder · June 13

4 of 5 times works well then failed.

bt_boot_fail_05.txt

Could you explaint it to me what you suggest to do?

As I see you tried to set logic level on PH1 pin on CPU. In accordance with schematic this pin is connected to debug UART (RX) signal and doesn't affect on wireless chip. So I don't understand what you try to do.

One more thing is BT and WiFi are in one chip, WiFi works well every time. As I understand the issue doesn't affect the chip itself otherwise WiFi wouldn't work either.

IBV · June 13

The actions in the dts for setting the GPIO pin are is based on the boot log line.

marlin chip en dummy pull up -- need manually set GPIO

You can check the whole discussion here and the reasoning

https://chatgpt.com/share/68466d15-e5bc-8013-b200-17ae7f7c89fc

However, After your last answer, Chatgpt suggests this is not really the issue, but a delayed initialisation would help.

When the bt fails to initialise, try the following:

sudo hciattach /dev/ttyS0 any 115200 flow
sudo hciconfig hci0 up

If this works, you can put this in a service to run at every boot.

You can try yourself to continue the above conversation with chatgpt and see if you find the final solution. Then you can post it here.

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Bluetooth doesn't appear after boot very often in Orange Pi 2W

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