Thank you for your advice about this way to reset to defaults.
This is not paranoia but a lack of precise technical knowledge about how exactly is processed the extraction of personal data and how the database works in general. I am currently trying to acquire this knowledge. Once done I will update the wiki with up to date information about registration bypassing with newer databases to prevent other users from struggling as I did with sqlite3 syntax. This topic is a part of the preparation process as I want to post accurate and useful information. This may also help me to recover my notes and bookmarks data.
Thinking twice before upgrading the firmware is also a good practice from a technical point of view if I want to keep complete control over my devices functions. For instance I also think twice before installing linux over window$ for hardware support reasons. Updating the firmware on my Kobo may or may not prevent me to do some specific hacks I may want to do in the future. I simply lack precise knowledge here too.
I am seriously considering to register if no other solution can be found and I am not terrified that my readed books associated with my IP goes somewhere in the big data as you may think. This is just a posture I assume to be coherent with my ethical choices. Not wanting to sign the EULA, which is a legal document is part of this conscious ethical posture. Freedom means being able to choose consciously to register or not to register. It requires technical knowledge. I also like to hack things.
Can ExcludeSyncFolders option be useful here ?
https://www.mobileread.com/forums/sh...d.php?t=341052. If I understand well this may prevent the device from scanning .kobo and .kobo-images folders into the database. If I understand well the data telling I'm not synced is already inside the database, meaning this option is useless to me but also meaning the database is the good place to investigate about data syncing.