Resources and other information
Latest versions can be found here this page bypasses lenovos stupid ftp download system
Latest BR10i firmware can be found here
The installer will say "platform not supported" but its lying. Use 7zip to extract it, run the update yourself using sasflash. The recommended way of using sasflash is via MSDOS but thats.. just not very gaming. I updated in the following order. update bios -> update firmware.
A PDF containing all the commands for sasflash can be found here you should read this, so you can make sure sasflash wont overwrite the incorrect device
Also remember to install the latest driver
Updating to the latest version allowed me to use ServeRAID BR10i with UEFI, Windows 10 LTSC 21H2.