Ok, a little update.
As neither 192.168.2.100 nor 'tnas.local' was working, I relaxed temporarily the firewall rules and allowed udp ports 5353 and 53791.
I tried again 192.168.2.100 (not working) and 'tnas.local' which was indeed working :
Got through the installation procedure flawlessly with NO DISK inserted yet, BUT the SSD cache :
Not wanting to use the SSD as storage, I inserted HD1 (been "formatted" on Windows) :
Deselected the SSD :
Installed TOS :
Reboot, strangely 'tnas.local' doesn't work anymore, but now 192.168.2.100 does, go figure.
Set the user/pass :
Created a first storage as "JBOD" because going to remove it anyway to then create one with all the 9 HDs from the HMI :
Looking good so far :
BAAAM, bootloop, I'm sent back to user/pass :
Crossing fingers and toes :
Yeah Baby :
Let's delete the volume FIRST and THEN the storage pool :
Now let's add all the HDs one-by-one :
The NAS doesn't look like synchronizing anything, seems good, let's create a storage pool with ONLY the HDs :
Fi-na-lly, what a journey to get there, now the NAS will work for about 30h...
What remain to be done is the volume creation, yet how to set it to TRAID+ (aka TM's RAID6) instead of TRAID (aka TM's RAID 5) ?
Regards
Broken 
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