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

Actually if you check the brightness sensor output, you’ll notice the sensor is rather limited, it cuts off way too soon, on both sides (dark and bright), thus erroneously reporting total darkness or full sunlight when it shouldn’t. It also has quite a steep response curve (resolution too low?).

If the proximity IR sensor is of similar built (or even the same part!) I am not surprised it reacts violently to passing tree shadows: Its output must be reporting a change from full light to total darkness with each shadow passing…


For me personally it’s adjusted perfectly. An OLED would’ve even be better at night and a higher max brightness would also be great. But other than that I’m satisfied for once :stuck_out_tongue:

I actually can’t, because I don’t have the order number for the smartphone. I can’t even activate my warranty, since I don’t have the original receipt. I wish I could somehow get the order number from the IMEI.


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The order number shows you are the legitimate owner, if it could be done by the IEME then a ‘stolen/found’ phone owner could circumvent access etc.

So why do you not have the receipt, do you not even have an email? If you bought second hand or it was a gift contact the buyer.

Alternatively you can initiate contact with Fairphone via email support@fairphone.com

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HW: FP4, 5G, 256 GB
SW: recently updated to Android 12
Display-Setting: Brightness 100% / automatic dimming function disabled
Akku: 70-100% loaded

Independet from environmental lightning conditiones after a random operating time (0-30 minutes) the display will dimm down to approx. 30-50% brigthness. Too less, to read comfortabely or see what e.g. car-navigation at a sunny day shows. After an additional random time (minutes, houres) suddenly the brightness will return to full brightness. I could not find any correlation to a specific app or operating mode. Seems to be compleley random when and how long the display will become dimmed down.

Is there a correlation do Android 12 - Update? When will bugfix be available?
Defect Display?
SW-Bug in FP4?

Thank you for your fast assistance

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hi and welcome, there seems to be some bug, please see above.

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Welcome Powerfrau and thanks for the info.

Please remember that this is just the community forum: you need to inform official Fairphone Support of your problem, even if it has already been reported by other users.

See how to > #contactsupport

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Was purchased it by my dying grandfather. He didn’t bother to retain the receipt, to my knowledge.

I suggest you use the web-form you already tried, to get in touch with support. Explain your situation and add any supporting details you can, such as

  • when bought (even approximate like “late 2021” but be as specific as possible)
  • from whom : online shop? Network operator? A store somewhere?
  • name and address of purchaser

You could offer to provide the IMEI but don’t cite it in your initial message.

Important: in the drop-down list “What is your request about”, choose “Something else”. That way, you don’t need the order details to complete the form.

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Random brightness changes: Just for the record, I got some too yesterday. I was reading something on the phone in a not very brightly lit room, without moving (nothing to change the amount of light the brightness sensor receives), and yet, all of a sudden, it got brighter. Then, a couple seconds later, it dimmed back to the previous level.
I moved the phone a little to see if I could trigger it again, to no avail. Go figure.

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That’s the very low level, bored to bits AI trying to get your attention. The AI world can be very lonely.

:open_mouth: OMG. Cat is very jealous, if it finds an AI on my lap it will shred it to kilobits.



I have noticed that after updating to android 12 (kpn, so not too long ago) my screen brightness will randomly drop even though the screen brightness is at full. I have also noticed that when it happens the last quarter of the screen brightness setting doesn’t actually dim the screen more as it seems to have hit the lowest setting. The lower max brightness makes it really difficult to see the screen in sunlight, and is quite annoying. Sometimes it randomly becomes brighter again though. I have checked my settings and extra dim is off.

Does anyone know what’s going on?

Thanks in advance!


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.