Thanks for the support.
It was possible with the UEFI tool sas3flash.efi.
The information [2] from the manufacturer just states, that i can not directly crossflash IR to IT. But it was possible the default way with
sas3flash.efi -o -e 6
sas3flash.efi -o -f firmware_IT.bin
sas3flash.efi -o -b bios.bin
BUT i actually recommend trying to do it in one command first because
it validates the firmware you have to use later, before its to late.
It tells you something like this:
FS0:\sas3flash.efi -l LOGFILEFLASH.txt -o -f SAS9300_8i_IT.bin -b mpt3x64.rom
Advanced Mode Set
Adapter Selected is a Avago SAS: SAS3008(C0)
Executing Operation: Flash Firmware Image
Firmware Image has a Valid Checksum.
Firmware Version 16.00.10.00
Firmware Image compatible with Controller.
Valid NVDATA Image found.
NVDATA Major Version 0E.01
Checking for a compatible NVData image...
NVDATA Device ID and Chip Revision match verified.
NVDATA Versions Compatible.
Valid Initialization Image verified.
Valid BootLoader Image verified.
ERROR: Cannot Flash IT Firmware over IR Firmware!
Firmware Image Validation Failed!
Due to error remaining commands will not be executed.
Unable to Process Commands.
Exiting SAS3Flash.
Which is great because you know your firmware is correct before actually erasing the old one from the device. if you erase the firmware and dont have a correct new firmware it will brick the device on reboot. so i can only advise you to do it this way. Then it tells you, that it is not able to overwrite IR with IT. which basically only means you need to rease the old one before wrikting the new one. Do it and confirm a working bios with sas3flash.efi -listall. I had to reflash bios because i mistakenly used bios64 rom instead of bios32.
In the end everything worked great and i could boot right into the controller.
Thank you for your support.
I can now happily report:
LSI SAS9311-8i SAS3 works when flashed to IT
Best Regards,
prash3r