I`m finally found Supermicro CD with that version of driver supermicro.com/wdl/CDR_Images/CDR-X6_1.13_for_Intel_X6_platform.iso . Unfortunately, drivers in 'WIN98' folders are byte to byte the same as Intel's 10.3, release 8.0.27 . So we have a tombstone here.
BTW, in what topic here people calls for detectives to find missed updates? I have quite a numerous list of unsolved losses.