[vbox-dev] VM Memory space: region in BIOS - patching/override possible?

Arioch the_Arioch at nm.ru
Tue May 31 12:29:13 GMT 2011

Hello, all!

i have an old box ( 128MB RAM, 13GB HDD, DOS + Win98 - and that is after
several upgrades :-)  )
      it has a DOS program, that can maybe never be used, but need to be  
      the program is copy-protected: is "attached" to last 16 bytes of BIOS,
those F000:FFF0 to :FFFF
      the rest of BIOS is not to be the key, but "BIOS creation date"
definitely is.

      Can this be reproduced in VirtualBox or VMLite ?
      I mean that part of "stock" BIOS been replaced by pre-given data and,
possible, write-protected like BIOS on real hardware is ?

// BTW, it does have some LPT port with key as well, but that's a
different story, i hope :-)

      i do not need the whole BIOS. only a little part.

      last 16 bytes are reserved for
      1) 5-bytes JMP FAR command, for CPU cold-start
      2) the rest is BIOS creation date and is not code. I don't remember if
plain text or BCD or something.

      Both these can be harmlessly patched, after virtual machine CPU

      But that may require some plugins creation (if there is proper API) or
even some source patching, creating API/settings.
      So, since you have knowledge of internals of VBox, i think u maybe can

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