Thanks to Harley and Daniel for the good info; I was able to get my dead ZD1100 going again and get the campus WiFi back online. I used a generic 2GB thumb drive to replace the failed one. When it goes into Rescue mode, that's when it's helpful to have the serial port connected, so you can see what is happening when the web gui has frozen or timed out. I also had to resort to 9.3.0.0.87 to get an image that would not error out due to insufficient memory, but after that I was able to successively update until I got back to 9.8. We stopped at 9.8 (where it was before the failure) because of the issue with the security file after 9.9 preventing further upgrades, and because we are going to replace this unit ASAP; but at least everything is functioning again, and people can extinguish their scalps because of extreme WiFi withdrawal.
