Thanks Dan, As I stated above, managed to revive dead ZD1100 by cloning another working USB, So the vintage USB worked when cloned, but no good trying FDISK rescue mode.
That's awesome. I'll be trying that here in the next couple days. Also, to confirm: I just got the first of two used ZD1100's in today. It had 9.8.x installed. I downgraded to 9.7.x, then upgraded that to 9.10. It's deployed and working fine.
Just to follow up - I successfully cloned the stock USB drive using dd. I made an image file as a backup, then wrote that out to a new, generic 4GB stick. Works perfectly. With any luck, wear-leveling will make it last longer than the original.
Did you have a valid service contract on the ZD1100 you upgraded to 9.10? I was told the 9.10 checks for this before letting you upgrade. (I just bought a used ZD1100, and am trying to find the latest fw I can use)
Daniel I'm tinking about buying a zonedirector 1100 that powers on but won't boot on ebay for my R600 and r700 to coexist properly at home. I presume that it was pulled from a working environment and hard reset for too long. Would it be possible to get your cloned image as you've had success so I could just switch out the USB? Thanks Richard