[Someone]

FTA: “Amazon also warned performing a factory reset on affected Kindles will make them unusable.”

How does that work? Does a factory reset require access to an Amazon server? Did an update break the factory reset mechanism?

[m-p-3]

It's likely that the onboarding system for activating and linking the Kindle to an account will no longer work after a factory reset, and you will not be able to progress further.