Downgrade or Switch IR/IT mode for LSI 8211-8i

1. Erasing the rom is inevitable, so this can only be done under DOS or UEFI shell. And remember, do NOT reboot between erasing and flashing stages.
2. Commands are:

[sas2flash] -o -e 6
[sas2flash] -o -f [firmware_name] -b [rom_name]

3. For DOS, use rufus to create a bootable DOS/FreeDOS usb stick and copy flash executable, firmware and bios. Boot from usb stick and run commands.
4. However, for modern computers, this probably gives error "ERROR: Failed to initialize PAL. Exiting program."
5. So the only way is UEFI shell. If your motherboard has EFI shell then just enter shell and run commands.
6. For gigabyte hybrid EFI motherboards or similar without shell (e.g. GA-Z87X-UD4H), use rEFInd image instead, and flash with rufus's dd image function as those motherboards do not support UEFI booting from anything other than EFI partition.
7. Unfortunately sas2flash utility requires EFI shell ver. 1, it will give error "InitShellApp: Application not Started from Shell".
8. Download ver. 1 shell from edk2. Put it on root of any disk/removable media. Boot into rEFInd and it will show option to boot from ver.1 shell.
9. Find sas2flash files with "map -b" and enter corresponding filesystem with fsX: (X is partition label, 0…1 and A…Z) and cd.
10. Run commands.