Think you don't understand well. The fvdw-sl console will upload a standalone kernel that fully runs from RAM and it does not need need a disk or any firmware running on the nas. This standalone kernel can be used to investigate, repair the disk and to install fvdw-sl firmware . Your pc will communicate with this standalone kernel running on the cloudbox using a telnet client on your windows pc (is part of the fvdw-sl console package).
But if you prefer manual way there is this guide for manual install version 11-0 on a nwsp2
http://plugout.net/viewtopic.php?f=7&t=336#p2043. It will also work for a cloudbox. After that you will need to upgrade to 15-3 and to higher versions. We don't advise this manual method as working with the fvdw-sl console us a much easier way and faster as it use scripts to di all the required installation steps.
Ps a blue flashing light indicates that the disk is not recognized by the bootloader. This could be a dead disk.