M55Hi Plus Rev B ISA/PCI ATX Motherboard MBD001074-xx
"There are currently three revisions of the M55Hi motherboard, (Rev A, B and D). To confirm if you have a Rev A or Rev B/D motherboard, look on the back of the computer where the sound card input/output jacks are located. If there are four (4) jacks use only BIOS revisions 03 or 04. If there are three (3) jacks, use only BIOS Rev 09 (or higher). PLEASE NOTE USING BIOS REV 09 (or higher) ON A REV A MOTHERBOARD WILL RENDER YOUR SYSTEM NON-FUNCTIONAL, I.E. IT WILL NOT BOOT.
Rev 09b BIOS flash for Micronics M55Hi motherboard, Rev B only. This flash includes support for MMX. PER THE ABOVE INSTRUCTIONS PLEASE CONFIRM THAT YOU HAVE A REV B MOTHERBOARD BEFORE USING THIS BIOS UPDATE.
NOTE THIS BIOS FLASH WILL NOT WORK WITH OS/2."