WARNING: This page is about a different car, the 2025 BMW M4, 2024 BMW M4, 2023 BMW M4, 2022 BMW M4, and 2021 BMW M4. However, it is still accessible from the selected car via links, so may be relevant.
Loosen nut (1)
(covered) from the top (see arrow) with reversible ratchet and 10 mm hexagon socket and slacken line clip.