Safely Unmount the external SD card and remove it . In a little while with an internet connection , you will get a notice of an update for BMW, etc and just re-download it to the tablet. Don't have the SD card in the tablet if you are updating.
From what I understand is once the system is updated to a higher numeric level than when the Scan Folder was made at an earlier time when the system version level was at a lower numeric number , then the backup scan folder will no longer work. I did my back up of the scan folder to a 32 gb USB thumb drive a couple weeks before my updates expired , and it took a good 6 hours of time , and I wrapped a large block of blue ice in a towel to keep the tablet cool against it.