Originally Posted by CapnGoat
As far as my search, for what indexing would look like on a Kindle, conducts indexing would only happen after registering/setting up the Kindle. ...
The indexing I am referring to is the word search index creation that the Kindle does every time a new book is added and every time a change is made to the "My Clippings.txt" file (e.g. setting a manual bookmark, adding a note, ...). To tell if there is a background indexing process ongoing you simply do a Search from the Home screen, searching for some unfindable string (e.g. "qwqwqw", ...). The Kindle will, after a pause, report the number of hits (zero in this case) and will note the number of as yet unindexed documents.
If a number other than zero unindexed documents is reported highlight that number and click to get a list of the unindexed documents. Delete these documents before attempting a firmware update.