I followed a similar procedure to get my system back up and running.
My mobo had 8 SATA ports. I have 8 x 3 TB disks connected (RAID5, BTRFS). I was screwing around with the system and ended up bricking it trying to upgrade to the latest DSM.
The steps I took are:
1. Shut down machine
2. Unplug all HDDs
3. Plug in a single 120GB SSD to sata port 1
4. Basically re-install DSM 6.1.7 (which is what I had before I started), get it to a working state
5. Shut down machine
6. Attach disks to ports 2-8
7. Boot up machine
8. The array was detected and online'd, but in a 'degraded' state. It also said it had a crashed system partition on it - which I repaired.
(This is expected, beacuse I only plugged 7 of my 8 disks back in)
9. I hot-unpluged the 120GB SSD from step 3 and plugged in the last HDD - then initiated a RAID repair.
Everything back up & running now but obviously I lost all settings, apps, app customization etc but this is really simple to recover from (just reinstall apps, the data is there already)