Internal BT wont work if USB-dongle is attached at boot

[Appelg]

This is probably a more generic BT/Linux/Raspbian-question but I'll try since you might have had the same problem.

I bought the ZEXMTE USB dongle. Got everything working fine.

But with one problem: If the USB-ZEXMTE-BT-dongle is attached when I boot the RPI-zero-w, the internal BT-adapter isn't found.
Only way to do it is to first boot the PI, then attach the USB-dongle. Minor problem, but still an inconvenience.

Do you have any pointers on how to troubleshoot this?

[Appelg]

Ok so I figured it out.

The hciuart.service won't start if the bluetooth-usb-dongle is connected. Unless this is running, the internal BT-adapter won't show up.
No idea if this is working as intended or if I did something wrong.

Workaround:

• disable USB device
• start hciuart.service
• enable USB device

[djwasser]

@Appelg - thanks for the info. Using this as a start I modified run.sh on my installation so that the keiser service is able to start automatically on powerup/reboot. I used info from here to figure out how to enable/disable the specific port the USB BLE dongle is using and put that into run.sh
Pretty much of a hack, but everything starts up and works fine and has been rock solid. Here is contents of my modified run.sh for reference:

#!/bin/sh

echo '1-1.3' | sudo tee /sys/bus/usb/drivers/usb/unbind
sudo systemctl start hciuart.service
echo '1-1.3' | sudo tee /sys/bus/usb/drivers/usb/bind

hciconfig hci0 up
hciconfig hci1 up
/home/pi/.config/nvm/versions/node/v10.22.0/bin/node index.js

[Appelg]

I did about the same, works well!

[robcalm]

I was living with this issue too. Thanks very much for the workaround!

[nealjane]

Dont think the extra text has worked in my run.sh as it didn’t show until I pulled and plugged in the extra usb bluetooth after boot for some reason..

But, I’ve worked it out -
echo '1-1.3' = is specific to you as you are probably using a hub,
By altering it to - echo '1-1' Switches off everything on my usb for 10 seconds (whether I’m using a hub or headless with only Bluetooth plugged in)

[djwasser]

@nealjane @robcalm @Appelg @hypermoose:

FYI, I found what I believe is a better and more generic fix for the BT startup issue. As sudo, edit /etc/rc.local and add the following line:

modprobe -r btusb && systemctl start hciuart.service && modprobe btusb

/etc/rc.local runs on reboot after all of the system services have started and before switching to multiuser run level.

Then the (non-generic!) lines added to run.sh are no longer needed and can be removed:

echo '1-1.3' | sudo tee /sys/bus/usb/drivers/usb/unbind
sudo systemctl start hciuart.service
echo '1-1.3' | sudo tee /sys/bus/usb/drivers/usb/bind