INT 13 - HyperDisk v4.01+ - ???
        AX = 8EEFh
Return: CF set
        AX = CS of HyperDisk resident code
        ???
Note:   identical to AX=8EEEh in HYPERDKX v4.21-4.30
SeeAlso: AX=8EEEh,AH=EEh