It's that time of year again for an upgraded flash script. This latest version is the easiest yet and again will flash from stock to u-boot and back. As usual, the goods are at the bottom of this post. I've added some fancy new features like progress bars.
Edit: To use the flash script, extract the contents of the zip file to a FAT formatted SD card, put it in a stock or ubooted zipit and power on. The zipit should boot to the menu, if it does not you did something wrong (try again) or the zipit does not like your SD card (try a different card).
There's a not so fancy new menu with the following options:
Backup: This will create a backup of whatever currently resides in the Zipit's flash memory. The mtdblocks, md5sums and offsets are saved to the flashdump directory on the sd card with the name you choose. The install does NOT ask you to create a backup so you should do this first.