This is where most users fail. BMW systems are picky. You need a USB 3.0 drive with at least 32GB (for map updates) or 8GB (for firmware). Crucially, it must be formatted as . NTFS will not be recognized. Additionally, the USB port in your car matters: use the port in the center console or glovebox designated for data, not the charging-only port in the rear seats.
Disclaimer: Software updates vary by model year and region. Always refer to your owner’s manual. This guide is for informational purposes. Improper updates can void warranties if done incorrectly.