Linux utility needed in Windoz

   What i need to do is turn on/off the boot bit(byte).

   Right now i can copy one or more partitions, thereby adding the 
requisite 100MB system sector to a windows system, making it usable.
   But without that magic mark, it is not fully testable.

   Yes, one could use Partmagic, but that requires re-cabling the 
computer and switching the OS.
   Big PITA.

   The Linux DD routine has been emulated for Windoz, so why not a Linux 
routine for this?

    Thanks.