Int 15 Fn D803  - Eisa System ROM - Write Nonvolatile Memory               [X]

   AX = D803h
   CX = length of data structure (0000h = empty slot)
       includes two bytes for config file checksum
   DS:SI -> configuration data

Return: CF clear if successful
       AH = 00h
   CF set on error
       AH = error code
       84h error clearing CMOS
       85h EISA CMOS is full
       86h invalid BIOS-FW function call

Note:  call with AL=83h if using 32-bit CS addressing mode instead of 16-bit

See Also: AX=D802h