For what it's worth, here's an update on installed OTA 07/2020.54 software on 2021 M550.
1. Car didn't brick....
2. Did it outside and took about 20 minutes
3. It did reverse some of my Bimmercodeing, not sure how much but ASS is still "last setting"
4. Daytime driving lights now both front and back, both on or off.
5. Seemed to move a couple things on instrument display.....not sure what exactly.
6. Some previous iDrive settings dropped out so needed to be reselected.
7. Gained 150 HP and a fresh cup of coffee was waiting in the cupholder.....maybe.