Blockquote what is your information based on that performing a factory reset with the SIM cards being removed should fix the issue?
I contacted customer support and got the advice to install the update without the SIM card.
Blockquote As mentioned in post 21, performing a factory reset has not helped. Granted, @DanSmith mentioned that he had removed the SD card but didn’t mention the SIM there, so it might after all be a different situation.
If you check his post he is still using 0033 and not 8901.3.A.0045.20200905 as I recommended in my post above
Blockquote but before performing a factory reset and invest hours over hours again in backup-restore-and-reconfigure activities
If you use the Google Backup functions automatically it takes you not so much time, except for maybe copying pictures and videos to a computer. The reinstallation of all apps (approx 120) took me 10 minutes.
As for the rest, if you want more information be sure to contact Fairphone Support. I just followed their advice and for me it worked