bcdedit /export This command exports the contents of the system store into a file. This file can be used later to restore ...

bcdedit /export 

This command exports the contents of the system store into a file.  This file
can be used later to restore the state of the system store.  This command is
only valid for the system store.

          The filename to be used as the destination for the export.
                    If the filename contains spaces, it must be enclosed in
                    quotation marks ("").

Example:

The following command exports the system store to the specified file:

    bcdedit /export "C:\Data\BCD Backup"