@[email protected] did a SecureErase, which is an entirely different function. It was exactly made to be used in this scenario: user is selling their laptop.

other than that, hdparm --trim-sector-range is most probably only marked dangerous because with a slight miscalculation you can wipe some of your data and you won’t even know how much damage you did. I’m pretty sure the fstrim command relies on this, which is executed every few weeks on my system, by default. check systemctl status fstrim.timer, maybe on yours too.

Quick formatting should be enough to prevent any normal user from extracting meaningful data from the flash storage as only the controller knows how to piece together the flash cells to a file.

what do you mean by quick formatting? how do you do that on linux? I have only heard this term with te windows disk management tool.

on windows quick formatting only deletes the partition entry from the partition table. that’s why it’s quick. all the former data is there and can be easily recovered, given you know the former partition boundaries, which can also be recovered by tools. the ssd controller won’t know a thing, it won’t forget where it should look for each LBA address.