5big Network2 rebuilt, won't work after restart.

Hi!
Hoping someone can shed some light for me here.
So I have inherited a 5big2 which had an issue, apparently had 2 disks failed previously which were replaced, but then unable to get into the dashboard (dashboard entirely blank). Tried a reset using the big blue button, which reset to DHCP (previously had a static address) but still same behaviour.
Tried to update using the LaCie Network Assistant, unfortunately this doesn't see the drive. If I start the 'recovery mode' and fire up the NAS the NAS seems to hang (after all drive LEDs come up they all go off, then nothing happens, no network traffic goes out of laptop). Tried using the fvdw-sl console from here, and I get the same behaviour as above where the NAS hangs on startup using any option and no output from u-boot console.
This issue may be down to firewall / HIPS software on laptop (I am at work), I have tried disabling what I can but still same issue. This isn't in itself a massive issue, but does mean I can't see what's going on with u-boot output, and I can't use the network assistant tool to upgrade firmware.
OK, so skip forward, I try to have a go replacing the firmware using the files on this thread: viewtopic.php?f=26&t=1955
I fix up one drive, put it in slot 1 and fire it up - this has more success, I get the NAS to boot up, it picks up an address, I can get into the dashboard and everything looks hunky-dory! ... until I restart the NAS. On restart it seems to start up (drive lights flicker promisingly), but doesn't lease an address so is effectively dead to the world.
Try again with 1 fixed drive and the others blank in other slots, again fires up fine, I can set up RAID, it goes through a sync overnight, everything looks great ... until I restart it when once again it's dead.
Any ideas?
Are there any OS limitations on the Lacie s/w or the fvdw-sl tool? I've tried on W10 and W7 but seems same behaviour.
The only other thing I can think of trying is to do a firmware update from the dashboard on the first good boot - unfortunately I can't do this here as I have no internet connection on the network I can use for this, but I might see if I can take it elsewhere to try.
Thanks for any pointers!
Hoping someone can shed some light for me here.
So I have inherited a 5big2 which had an issue, apparently had 2 disks failed previously which were replaced, but then unable to get into the dashboard (dashboard entirely blank). Tried a reset using the big blue button, which reset to DHCP (previously had a static address) but still same behaviour.
Tried to update using the LaCie Network Assistant, unfortunately this doesn't see the drive. If I start the 'recovery mode' and fire up the NAS the NAS seems to hang (after all drive LEDs come up they all go off, then nothing happens, no network traffic goes out of laptop). Tried using the fvdw-sl console from here, and I get the same behaviour as above where the NAS hangs on startup using any option and no output from u-boot console.
This issue may be down to firewall / HIPS software on laptop (I am at work), I have tried disabling what I can but still same issue. This isn't in itself a massive issue, but does mean I can't see what's going on with u-boot output, and I can't use the network assistant tool to upgrade firmware.
OK, so skip forward, I try to have a go replacing the firmware using the files on this thread: viewtopic.php?f=26&t=1955
I fix up one drive, put it in slot 1 and fire it up - this has more success, I get the NAS to boot up, it picks up an address, I can get into the dashboard and everything looks hunky-dory! ... until I restart the NAS. On restart it seems to start up (drive lights flicker promisingly), but doesn't lease an address so is effectively dead to the world.
Try again with 1 fixed drive and the others blank in other slots, again fires up fine, I can set up RAID, it goes through a sync overnight, everything looks great ... until I restart it when once again it's dead.
Any ideas?
Are there any OS limitations on the Lacie s/w or the fvdw-sl tool? I've tried on W10 and W7 but seems same behaviour.
The only other thing I can think of trying is to do a firmware update from the dashboard on the first good boot - unfortunately I can't do this here as I have no internet connection on the network I can use for this, but I might see if I can take it elsewhere to try.
Thanks for any pointers!