BIOS & Bluetooth

Inspiron XPS 8900

Windows 10

I have a Bluetooth keyboard and mouse. They work fine with this PC when windows 10 is running.

But the keyboard is not detected on start up and gives an error screen in an infinite loop. So it seems the bIOS does not recognise Bluetooth.

The Bluetooth mouse and keyboard work very well once Windows has loaded and I can login to Window with those devices. BUT to get to that point I must have either a wireless keyboard adapter in a usb port, or a wired keyboard in a usb port. The PC will then boot and present the Windows signon screen. From then the Bluetooth devices can be used (including for signon).

But I cant boot without having an old keyboard available.

Sort of defeats the purpose of using Bluetooth -- which was to save a usb port.

Is there a workaround, or a BIOS update, that will allow the PC to detect the Bluetooth keyboard and proceed to boot?