FWIW, as the log confirms, the JB would only actually be properly installed by the bridge on your next reboot. The JB script isn't designed to run from diags, only from the main system, hence it only did half the job, and left the rest to the bridge.
Not a huge issue with recent versions, but that didn't use to be the case, and it needed to be said

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Sidenote: KindleTool can handle the password stuff just fine (via the info command), if dealing with Python is an issue.
Apart from that: love it ^^.