your current BIOS is 54, so you want to downgrade your BIOS? you can try using latest BIOS. And make sure download the corrected BIOS for your board.
Yes, I want to downgrade it. I am downloading it from the downloadcenter http://downloadcenter.intel.com/SearchResult.aspx?lang=eng&keyword=%22Intel+Server+Board+S5500BC%22
so do u suggest I should try upgradeding?