I got this response from Fairphone:Am Mittwoch 25 September 2019 16:07:36 schrieb Paul Boddie:On Wednesday 25. September 2019 15.17.24 Carsten Agger wrote:I send the following question to Fairphone support: "I'm interested in buying a Fairphone 3, but I'm not interested inThanks for requesting this, I think it is helpful if potential customers voice their preferences for Free Software.
It is still possible to install alternative operating systems on our Fairphone 3 (advanced users can unlock the bootloader - but this voids the warranty!), however, we do not offer support for any different OS."
The "Fairphone Open" option looks interesting, but the thing
about voiding the warranty if you unlock the bootloader is not
good enough.
It is, on the other hand, completely understandable that they
can't offer support for other OS's.