F2-210 does not recognise drives

[reynoldsce]

The F2-210 unit I had failed so it was replaced with another F2-210. It was running RAID 1 with 2 x 2Tb Skyhawk HDD's. The HDD were inserted into the replacement unit but that does not load TOS.

The drives have not been wiped but when viewed using Terminal (Mac OSX) and extFS for Mac it's only possible to see the "lost & found" folders. Using R-Studio the full file structure is visible.

I can get TOS installed and the unit up and running if I drop 2 replacement disks into the F2-210.

Any thoughts on how to retrieve / access the drives under TOS or is this likely to need a recovery service?