ReadyNAS boot failure - pulsing power LED

Thanks for the reply. I've just edited my original post before realising your reply was there - the error code I originally described, and which your reply addresses, is when one disk (disk 2) is removed. When both disks are in, I get a pulsing power LED - four pulses followed by a single blink of the Act (activity? LED). No other LEDs blink.

The ReadyNAS is a Duo v1, bought May 2010. I tried earlier to do an OS reinstall (by holding down the reset switch with a paperclip for three seconds on power up, right?), but it did not appear to enter into reinstall mode, instead just booting as normal (if normal is the blinking LEDs I describe above!)

I'll have to hunt out my hard disk caddy from the garage in order to test the disks with vendor tools - a job for the weekend. In the meantime, to answer your other questions, yes I do fortunately have most of the data backed up (phew!); I can't recall which firmware is running, although I've tended to update it fairly regularly. AndI don't think ssh was enabled...

Thanks again.