// ntddk.h
NTSTATUS IoSetSystemPartition(
[in] PUNICODE_STRING VolumeNameString
);
View the official Windows Driver Kit DDI referenceNo description available.
The IoSetSystemPartition routine sets the boot partition for the system.
VolumeNameString [in]Pointer to a Unicode string that specifies the MS-DOS name of the system partition.
STATUS_SUCCESS if the boot partition can be set, or an error code on failure.
The specified partition must contain the boot loader.