Microsoft DOS fixboot command
The fixboot command is a recovery console command that creates a new partition boot sector.
The fixboot command is a recovery console command that is available in the below Microsoft operating systems.
Writes a new partition boot sector to the system partition. The fixboot command is only available when you are using the Recovery Console.
Drive is where the boot sector will be written. This replaces the default drive, which is the system partition of the machine you're logged into.
In the above example the boot sector would be written to the C: drive.