Vikram's Web Archive

bcdedit /store S:\Boot\BCD /set {9dea862c-5cdd-4e70-acc1-f32b344d4795} device partition=S:
bcdedit /store S:\Boot\BCD /set {b2721d73-1db4-4c62-bf78-c548a880142d} device partition=S:
bcdedit /store S:\Boot\BCD /set {466f5a88-0af2-4f76-9038-095b170dc21c} device partition=S:
bcdedit /store S:\Boot\BCD /enum all /v

DISKPART
select disk 0
select partition 4
active
First the system store is exported to S:,
then the references in that store file to partition D: are replaced by references to S:,
then the contents are printed out just for verification, just in case
then the boot sector was copied from DVD to S:
and finally DISKPART is used to mark the S: as active.

[From: Change Vista's 'System' partition / move BCD boot manager? - The NeoSmart Forums]