Updating infotainment firmware carries a risk of "bricking" the unit if the process is interrupted (e.g., the car battery dies) or if the wrong version is applied. It is highly recommended to connect a battery charger during the update. Additionally, updating may trigger a "B201A" fault code in the car's diagnostic system, though this typically does not affect performance.
If your diagnostic tool shows mst2-eu-vw-p0891d as a static (non-intermittent) fault, follow this flow chart. mst2-eu-vw-p0891d
To understand it better, let’s break the code down: Updating infotainment firmware carries a risk of "bricking"