RhoMobile on TC52, Android 8.1: "DS8178 Bluetooth Scanner is

Hi,

I am trying to get an existing RhoMobile APK running on a TC52, Android 8.1.
The App is running fine on TC51, Android 6. On the TC52, when i start the app I get a toast message

DS8178 Bluetooth Scanner is not connected, therefor BTPairing Utility will be started.

The problem is that - ignoring the BTPairing Utility App (i also tried to disable it) - i cant use the build in scanner in my rho mobile app. When I try to use it I see the following message in the log

"The decodeSound barcode property can only be set once the scanner has finished initialising"

Looking at the underlying code, it looks like that the scanner has not initialised, probably due to not be able to pair the bluetooth scanner. But there is now such scanner and there never will be. Anybody know how to disable this behaviour?

Here is my javascript code for enabling the scanner

Rho.Barcode.enable({ allDecoders: true }, this.onScan);
But, I think it happens before that javascript is accessed; the app is hosted on web server; even if i disable WIFI and starting the app, the toast is displayed without downloading any javascript code. It seems like that RhoMobile is trying to setup all known scanners.

Edit:

I tried to enumerate the available scanners and see which ones are available, and checking which one is default:

Scanners found: '[
   "Camera Scanner",
   "2D Barcode Imager",
   "Bluetooth Scanner",
   "RS6000 Bluetooth Scanner",
   "DS3678 Bluetooth Scanner",
   "LI3678 Bluetooth Scanner",
   "DS2278 Bluetooth Scanner",
   "DS8178 Bluetooth Scanner"]'

Default scanner: '2D Barcode Imager'

Update: 
When I "select the scanner" by using the `scanner` instance that matches the name `2D Barcode Imager` and use that instance to enable it, the scanner trigger works.

What remains is the toast that asks to connect the `DS8178 Bluetooth Scanner`; is there a way to disable scanner from config.xml?

I asked the same question on SO, they redirected me to here.