INT 6F - HP HIL Vectras - EXTENDED BIOS - WRITE CMOS MEMORY
        AH = 24h
        BP = 0012h (ID of V_SYSTEM driver)
        BL = address of CMOS byte to write
        AL = new value
Return: AH = status
        BP, DS destroyed
SeeAlso: BP=0012h/AH=22h

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