For some special reason, I want to make sure bluetooth is completely disabled. I have done the following:

 

1. Try to run hcitool & bluetoothctl. Both commands are unavailable on the system.

2. Run "systemctl status bluetooth", it says "Unit bluetooth.service could not be found." 

3. Run "service --status-all", it doesn't show bluetooth entry.

 

I'd assume bluetooth isn't enabled, but when I run "dmesg |grep Bluetooth", it shows:

 

[   13.744331] Bluetooth: Core ver 2.22
[   13.744337] Bluetooth: Starting self testing
[   13.761692] Bluetooth: ECDH test passed in 16935 usecs
[   13.764626] Bluetooth: SMP test passed in 2804 usecs
[   13.764636] Bluetooth: Finished self testing
[   13.764717] Bluetooth: HCI device and connection manager initialized
[   13.764729] Bluetooth: HCI socket layer initialized
[   13.764734] Bluetooth: L2CAP socket layer initialized
[   13.764748] Bluetooth: SCO socket layer initialized
[   13.778717] Bluetooth: Generic Bluetooth SDIO driver ver 0.1
 

What's the correct method to verify whether bluetooth is enabled on the system? In addition, what's the correct method to completely disable bluetooth? Any suggestions are appreciated.

You could test the options from this page:

https://unix.stackexchange.com/questions/387502/disable-bluetooth-at-boot

 

- via /etc/bluetooth/main.conf
           AutoEnable=false
- rfkill
           sudo rfkill block bluetooth
- lsmod / blacklist the modules

Thanks! lsmod / blacklist the modules resolves the issue.