Intel C222 chipset, latest Bios came with rste module 3.7. Updated to 3.8 and to 4.6. Had to reset all settings but a Raid1 consisting of two 6TB disks is recognized and usable as before, no advantages anyway.
Asus P9D-I, Bios 1801, programmed new chip with CH341A.
Quite old hardware, just in case someone might be interested.