Debricked it at lunchtime using my linux mint machine. (It helped that I already had the original firmware images on my data drive)
Basically - open the enclosure - (snapped some tabs but seriously those are a PITA to not break em)
Followed these instructions: https://drive.google.com/folderview?id=0B_6OlQ_H0PxVRXF4aFpYS2dzMEE&usp=drive_web
with the following exceptions:
Got an error doing this step - mdadm --stop /dev/md127 - I assume that was because I wasn’t using a LiveCD
For these:
I changed sda to sdb (Again likely because I was using a linux desktop not livecd)
dd if=kernel.img of=/dev/sda5
dd if=kernel.img of=/dev/sda6
dd if=config.img of=/dev/sda7
dd if=config.img of=/dev/sda8
Remove drive - plugged in powered up - WD UI after deleting cache.
Stuck at the login screen - won’t accept default admin/admin. May have to do a system restore from the button on the back.
Update → Ok - back in - had to do 40 sec system restore - data is all fine. Set it all up again and I’m updating back to 623 for some testing. :)
Testing Results for reference:
With WD firmware v04.00.01-623 I’m getting the following.
myCloud → PC = 26-30 MB/s
pc → myCloud = 65 MB/s
Using my linux box right next to the myCloud on the same gigabit switch I got:
myCloud → linux = 30 MB/s
linux → myCloud = 43 MB/s
I verified that all machines were Speed: 1000Mb/s so I expect the limit on these is actually the drives.
For reference WD Firmware uses Version 4.0.0rc5 (I saved the samba_multicall, configs, smbd, nmbd)
-rwxr-xr-x 1 root root 5211800 Dec 12 2013 samba_multicall