Random Screen dimming (while brightness slider stays at 100%) after A12 update

A bug?

Please see above.

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This bug totally destroyed the phone. If it doesn’t get fixed soon I will sell it.

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Can you not just disable adaptive brightness for a while?

That doesn’t help. The brightness slider doesn’t move when this happens. (I.e., it’s set to 100%, but the actual brightness decreases.)


Hello, did you resolve the problem? I have the same problem with my FP4

The System Table reports screen_brightness is 255 when the brightness is correct. It also reports that value when it is incorrect. The slider, I expect, is operating correctly since manually modifying the Table does not actually change the brightness of the display.

The issue is probably at a lower level in the OS.

I’m quite confident that as someone mentioned previously, heat is the deciding factor, because I’m currently keeping my phone at 255 brightness to cause the problem to occur again, yet it’s not, and this place is tremendously more cool than where I have been using it at maximum brightness.

[ ] I’ve yet to evaluate whether setting a value higher than 255 (yes, it’s possible) when the brightness is buggy tricks it into setting the correct brightness.


Happened to me very often the last days. Already thought it was getting better. Very annoying since it is getting brighter in germany now.
Meanwhile I doubt that it has sth to do with heat. Also happened to me when the phone was quite cold.


I neither would say heat is an issue, I had it outside in sunlight and so far sunlight does not really cause heat like in the summer…

I’m just wondering whether this “sudden dimming” isn’t preparatory to the screen turning off. Since we all have different screen-on timeouts, different people are going to see different effects. You might (provisionally) try extending the following value:

Settings > Display > Screen timeout

to see whether that prevents the screen from dimming ?

Could well be. I’m testing a beta A13 on an FP3 and have something almost identical with my30 sec timeout

No it is not as discussed already above

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you use the FP3 and not the FP4 so how would you notice when we talk about a FP4 bug🤔

I thought so too, but then I did notice that my screen’s brightness is very slightly varying all the time (constantly?), even when and while I’m actively touching the screen. Most of the time it’s rather imperceptible, but sometimes, rarely for me, it becomes very noticeable.

Timeout might account for some occurrences, but there definitely is a different problem too.


For me it seems to be reproducible in the sun. Currently writing in a dimmed screen, brightness at 100% and difficult to see something… For me that def did not happen last year.


I was saying that it may not be a bug as OldRoutard speculated that it may be an Android intent, which as I have moved from 11 to 13 I see a similar issue. So I was saying OldRoutard maybe on to something which is Android 12/13 related and not Fairphone 3 or 4 issue.

It must be the way I comment as I’ve noted a few times you have interpreted differently than I meant. Even in the UK my place of birth people wonder what I’m talking about :slight_smile:

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So similar means, on the FP3 the screen dimms while you use it, and while the slider stays at 100% and it stays like this and you cant do anything about it, if you touch the screen or move the slider manually doen and up again or not? Sure it dimms before it locks, still under normal circumstances it will light up again, by shortly touching the screen. If its the same on the FP3 with beta A13, I would rather say they incorporated the same bug into the FP3 OS. I never had this neither with the FP3 Iode Android 12 last summer before I switched to the FP4.

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If they are not able to fix this problem, they should provide a downgrade to android 11.
I cannot stand this issue much longer

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did you open a ticket? I did so 2-3 days ago as it seem to be reproducible in sunlight. Instead of downgrading, did you think about installing a Custom ROM, I think I havent seen any report that this bug is also showing in any Custom ROM so far? They will not manage two Android Versions at the same time, so downgrading would mean you stick to security patch level what makes your phone insecure over time.

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I opened a Ticket and they said they would forward it to the respective department.
I would rather use an insecure andorid Version without this problem than a secure one with this problem. Actually it is the most annoying problem I ever had with a mobile phone ever since it makes the phone nearly unusable in a bright environment.
And I am really not motivated at all to read stuff about custum roms. I just want a phone that works but android 12 update really fucked up


I believe that they do:

  1. Visit
  1. Download


  1. Install it.