I tried to install Lil’Debi, it installed Supersu (or whatever it is called) on fairphone-open but both failed to work. Both failed to complete installation - but this is another issue.
What I want to do is a factory reset. I did follow this guide:
But instead of “Android System Recovery” the phone boots into “Teamwin Recovery Project”. Is this the same?
I did a reset with the Teamwin Recovery Tools and it seems to work on system level. However, I would like to restore the “Android System Recovery”, too. How can this be accomplished?