Problems with FP Open OS on Android 9

[Lorus]

I upgraded my Fairphone to the latest Open OS, as usual and described here:

Update Guide for a modified FP Open OS (with Gapps, Xposed and more)

When having other packages installed with FP Open OS (e.g. opengapps or xposed) it is possible that you will get stuck in a bootloop after an update, if not installing these packages again. Because these additional tools are installed on the /system partition, you need to reinstall them after every update, since the /system partition gets overwritten during the update. However, you should not loose data or settings, which are stored on your /data partition. If you have not modified your FPOOS …

Got the latest TWRP Version, the latest OpenGapps for Android 9 and finally ran both updates successfully.
As is tradition for my phone, things do not quite work after the update. OpenGapps does not work (this means none of the apps is able to open), but even worse:
Every 2 seconds, I get the message: android.process.media keeps stopping.
Of course I have searched this and other forums for this problem, but the presented solutions (clearing cache and data) do not help.
I also experience frequent random reboots.

My question is where to start fixing these 2 problems. Are they connected to each other, does one cause the other? If so, which one is the root problem and how do I fix it? Why does OpenGapps not work even though it updated successfully?

[yvmuell]

To me it sounds as if somehting went wrong during installation even if no error was noted. I would try to install OS and Gapps again to see if this helps and probably delete dalvik/cache after installation. And if nothing helps I would do a factory reset.

Else I would follow-up on the issue tracker

android.proccess.media keeps stopping (wird wiederholt beendet) (#43) · Issues...

[Alex.A]

Perhaps try starting in #dic:safemode? Can’t see precisely why this would help, but it might help determine where the problem comes from.

Edit: take a read in all the threads of the issue mentioned above, this solution is actually suggested.

[Lorus]

For the sake of completeness, here’s how i fixed the issue. Was definitively a weird one.

After updating the phone to the latest FPOOS (I don’t even know if the issue was related to the update), I received a voice message in Telegram which would not play. I could play older voice messages, and other new voice messages in Telegram or other messengers were fine.
After a while, it hit me that my problem could be related to that message and indeed: after I deleted it from the chat, the problem was fixed. A couple of reboots later, OpenGapps also continued working.
I still have no clue what was the initial failure, but now things are kind of fine. I still experience more random reboots than before the update, but only around one per day.