Apparently the firmware did not updated correctly. Good luck using SpinRite.
I wish that were true, then I could simply copy my data to my PC via Linux. Sadly it seems that the hard drive became corrupt.
For what its worth the update did take OK, and I suspect the drive was failing before the upgrade. I have 5 of these drives and this is the only one that failed and now thinking about it, I did notice slow tranfers on this unit.
Spinrite refuses to finish the repair flagging up an error on the data partition (which I will provide a link to below), but did manage to scan partitions 1 through 3. After plugging the drive back in to the controller, the admin gui is back fully working.
I am now trying to copy as much of my data as I can, then I’ll nuke the drive & do another surface scan - Assuming the drive is good - I’ll use the Mybook Format tool to put the partitions back, and mybook rescue for the OS. Should be like new again after that.