If you restored a disk image, a single disk image is adequate to boot the NAS unit.
Remove all other HDDs and insert the newly initialized HDD to boot the unit. next boot the unit to confirm the procedure.
You may re-use old HDD only if partitions cleared.
We recommend that you replace old HDDs with new ones.
Next boot the unit. Once booted, login to web UI and select Format from WEB UI to reinitialize the new HDDs.
*** If you decided to restore the boot sector only, you will have to repeat the process for all HDDs.
The boot sector only has not been tested.