I am giving up on Bluetooth.
I have tried: 2 dongles, 2 HC-06s, 2 different computers, 2 operating systems (ubuntu and Win), 2 helicopters, 2 different TXs, several different HC-06 configurators, all of that many times.
A Ubuntu 'expert' said Asus dongle works but ubuntu says it is identical to the Insignia brand dongle that I already own. It works for my phone but not for a heli.
When I have Telemetry (57600) configured for my 'Main Port' the heli usually won't bind to my TX. I tried switching to 'Flexi Port' with the same result. It won't fly. With USB connected it will respond to TX but obviously no data can flow through BT because USB is primary.
Both 250s (DJ250 and Amarillo) behave nearly the same and both have Spektrum DSMX sats and Atoms.
The only difference is that sometimes when Amarillo binds to my TX the #2 servo goes all the way to minimum without the USB connected. With USB connected it behaves better.
I reconfigured both for no bluetooth or Telemetry. I am going flying.