I've tried, having removed the 3TB again, completely wiping the data via PC, and reinserting, but same result. With SSH enabled on the ReadyNAS, I switched to using a Mac (as it has a Unix command prompt which includes an SSH client) but any Unix.
When you download a new firmware, it first copies it onto the flash memory and then installs it on the drives. The next step was to install the latest stable version (v0.4.17-1.0.1) of Stefan Rubner’s iSCSI target add-on for ReadyNAS (as for EnableRootSSH and ToggleSSH, it is simply applied as an update in FrontView). The firmware on the flash memory of your unit is currently the Beta. ReadyNAS includes a built-in FrontView Web based graphical user interface and setup wizard for ease-of-use and setup. What it does is wipe the drives of all data and settings, reinitialize the drives, reinstall the firmware from the flash memory and resynchronize the drives.
I tried rebooting several times, but nothing changed. You can also allocate iSCSI target volumes on a ReadyNAS 2100. Howvwer it only showed up as 2TB when the Ready NAS created the 2nd volume (reamining HDD is in slot one, if it matters). The NAS was configured as RAID 0 but separate volumes on each HDD, so having backed up the failing drive (mostly, couple of TV Show rips didnt back uP properly, no biggie, i can re-rip) i removed it and put in the 3TB. It has had two WD Red 2TBs in for a couple of years in my ownership (bought 2nd-hand), one of the drives had Smart errors so i replaced the failing dirve with an existing 3TB WD Red. Ive got the later version which runs Radiator 5.3.8 which is compatible with over 2TB HDDs. This item Netgear ReadyNAS Duo RND2000 Home Storage Solution (2 Bay) - No Drives Included TerraMaster F2-221 NAS 2bay Cloud Storage Intel Dual Core 2.