This is a situation that is not hard to recover from on an Android device. The key is the SD card which can be inserted - if this contains a directory named script, with the appropriate contents, the device will detect that and pause before entering update mode and a count down will be displayed on the screen. Hit a key (mine has no keys!) or pull the SD card if you do not want to proceed.
The next screen will display a series of messages as the environment is prepared for upgrade.
If all is going well (more on that later) the changes to the Android file system will be copied onto your device. This could include new applications or data. Anything really.
The one absolutely critical thing is not to run out of battery whilst this is happening and this, courtesy of a dodgy mains power connection, is exactly what happened. At this point this device was really truly lost. As far as I could tell the boot ROM code on the CPU daughter board had become corrupted and this simply cannot be replaced. The device went in the garbage!