I think Support once recommended SanDisk brand up to a 32GB size formatted in FAT32.
I think a few years ago a BMW update would also fail to install and the solution was to install a micro SD card and the update would install all or part of the BMW update on the external SD card. I didn't want any issues , so held off installing the BMW update until I bought and inserted a 32GB Sandisk Micro SD card, and sure enough the BMW update was put on the SD card. Later after another BMW update,a little under month before my update period expired, I wanted to back up all of my software from one location, so I unmounted the SD card and removed it and deleted BMW App. I then re-down loaded BMW and it all installed fine on the internal drive. I waited and created a backup of the entire Scan Folder on a 32 GB USB Thumb drive a few weeks before my update expiration because new system updates of a higher version numbers alledgedly renders the backup software with a lower numerical system update level unusable to successfully restore the software and be allowed to access it and use it again if you are out of the free update period