Since a week I’ve been using the Google Now launcher instead of the default Fairphone OS launcher. The updater downloaded the 1.6 version and did a reboot of the Fairphone.
Initially all seems to go well (installation of the update, updating of applications, booting the phone), but I ran intro trouble as Google Play services quits unexpectedly all the time. I tried to reinstall Google Play Services with the Google Play store, but Wifi network doesn’t work somehow.
Only way to resolve the situation is to deinstall the Google Now launcher (Settings -> Apps -> Google Now launcher -> deinstall). As soon as I exited the Settings menu the Fairphone intro music started. Installation restarted and now all is well.
In short - make sure you use the Fairphone OS Launcher before starting the update!
Good tip. It’s a well established problem that the Fairphone updates fail when other launchers are active - but I hadn’t come across the Google Now launcher yet (was only available for 4.4 kitkat devices last time I looked)
I have updated the title to make this easier for those with the launcher installed to find out about this, and I will recommend that the install instructions are updated to mention disabling alternative launchers before updating