T440p with external BT keyboard

[devinfriday]

Hi, I have bought a mechanical keyboard with cable and Bluetooth. Previously I used a Logitech one with the unifying receiver and worked fine but has a poor quality overall. The BT keyboard works fine, unless you don't want to enter bios or have grub as boot loader, because the Bluetooth pairing works only at OS level, right? Do I have to use it with the cable and switch to BT after OS has loaded? My T440p is connected to the docking station with external monitor and other peripherals.