I have purchased an Deciso appliance with OPNSense pre installed. I have managed to get the serial console working where I can see the boot sequence but I do not have serial console access.
System -> Administration settings are:
Console
Console driver Use the virtual terminal driver (vt)
Primary Console Serial Console
Secondary Console Serial Console
Serial Speed 115200
USB-based serial Use USB-based serial ports
Console menu Password protect the console menu
Am I missing something ?
Disable "USB-based serial ports" and set primary console to EFI console.
From the OpnSense perspective, the serial console is not USB, only the client uses USB via the provided USB/serial converter.