fastboot devices returns nothing while adb devices does Device is OnePlus 3. I'm unsure of why this is happening - I have made sure to install the fastboot and adb drivers correctly, however fastboot devices does nothing when I put it into cmd even though the adb devices returns my phone normally.
I found the solution - I needed to enable the installation of unsigned drivers on my system (Windows 10) and manually install the OnePlus bootloader driver while the phone was plugged in and in fastboot mode.