I was viewing a web page about tetanus vaccines on my Zaurus C700 Linux PDA when the machine froze. I rebooted it, it hung during the process, tried again, hung again. Tetanus paralysis taking hold.
After the next reboot attempt it refused to switch on again, the LED's just kept blinking. Tried again and again hard rebooting, pressing D+M . Got to the service menu once, but an attempt to reflash the NAND using a backup just lead to the message format failed.
I think I've "bricked" my wonderful Zaurus with bad NAND memory blocks and a corrupted bootloader. :( Now I"m really glad I decided to return via Japan for our next trip. Have to start saving now!
The forums here were useful diagnosing the problem and populated by very helpful people.