{L_BUTTON_AT}Toblerone
Have you considered that TM didn't manufacture the motherboards and only contracted for the bios supplied and/or the actual mnfr has never needed to supply alternative bios since the m/boards were manufactured for a specific (?industrial?) purpose. My Fn-221 models have basically the same m/boards but are subtly different. (reset push, 'proper' fan connectors as well the odd ones, one has 2 stacked usb on board).