[knc1]

You used the KindleTool to find your password.
Now use the KindleTool to extract the files from the Amazon update package.
(kindletool --help gives you the gory details)

At the top level of the output tree created, you will find a file named: rootfs.img
That's the baby we want to write to flash (or find out why not).

- - - -

That much above was alright.
The rest of the information, and the script, was trash.