Lumia 920s suffering from brightness bug with Portico update? Here's a possible fix.

Although the majority of people who are on AT&T or Rogers who have upgraded their Lumia 920 to Windows Phone “Portico” are having no problems (in fact, quite the opposite), there is one bug that seems to affect a few people: auto-screen brightness.

As detailed in our Lumia 920 forums, the problem exhibits itself when you turn on the phone in a mildly lit room and the brightness seems to ramp up to max and then back down again, resulting in a staggered and constantly fluctuating display brightness.

As forum member iamtim wrote:

“Now I'm sitting in my chair - where the light is arguably not quite dim but not quite bright - and it's acting like it doesn't know what brightness setting it should be on. It doesn't go from dimmest to brightest, but it is kinda like... "ok, let's dim a little bit! no, wait, brighten up a tad! no, too bright, dim down some! Er, no, go bright!" It's not happening very rapidly, maybe about every 10 seconds or so it changes a bit.”

Many people have chimed in saying they are seeing the same behavior as well. For some, disabling “auto brightness” helped while for others this results in eve “low” being too bright:

“I keep my brightness set to low with auto off. Everytime I turn off my phone and turn it back on it jacks the brightness to bat signal bright even tho its set go low. To correct it I have to set it to high then back to low.”

Personally, we have not seen this on our four Lumia 920s here at Windows Phone Central—that’s not to say it doesn’t exist, just that this isn’t a universal problem that one will automatically get if they update. In that sense, it's more a quirky side effect than a reproducible bug.

Possible solution?

The issue appears to be one of calibration of the ambient light sensor—that is when the update occurred, the device may have calibrated in bright light (or perhaps it really just “screwed up”). That little sensor (found near the earpiece) is misjudging the light in the room and it’s causing wonky behavior, to say the least.

The good news is there may be a fix, which is seemingly simple:

  1. Take your phone into a pitch-black room
  2. Power on
  3. Slide your lock screen up
  4. ?
  5. Profit

Seriously, some people are reporting that is all it needs, which in a way makes sense. The phone needs to get a baseline reading of light including very low/no light. Without a bottom to go from, the phone can get muddled on the range it should use. Letting the phone be exposed to pitch black for a few moments may be enough to re-calibrate the system.

Now since none of our phones are exhibiting this phenomenon, we can’t verify if the above actually works (though it has been a go to in the past). For that, we turn to you folks to see if this accomplishes the task and alleviates the oddity. If so, sound off in comments and don’t forget to share your bugs and any issues in our support forum.


Reader comments

Lumia 920s suffering from brightness bug with Portico update? Here's a possible fix.


Mine definitely has this problem. Gonna give this a try and I'll report back. Out of curiosity, does it only need one "dark" baseline measurement, or does this have to be done every single reboot?

How often would you reboot? I'm averaging once every 3 months or so... And that's only when I run out of power or switch out SIM's when travelling

Meh, didn't seem to help me. My phone still seems to be way too senstive with adjusting the backlight.
With my L900, I probably reset once every few months or so. Prior to Portico, I had to reset my 920 once every day or two because of freezes. Luckily after Portico, no freezes (yet) but the light sensor issue is annoying.

I was having this same issue. It was most noticable in my living room in the evening when the light is rather dim. I just went and powered on in a completely dark room and it seems to have helped, but I will not know for sure until I get home this evening. Thanks for the possible fix!

Saw this issue last night. It would go up and down quite a bit. Will try that 'fix' when I can find a pitch black room

Here's a fun fact... In the UK the words "pants" and "underpants" mean the same thing. The look of horror when I would be telling a story with something like "... and then they lost their pants" when I meant their jeans/trousers.

I think I noticed this on my 820, but I was happy for it- auto brightness hasn't properly worked on any phone; IOS, Android, WP, ever! Now I can see it doing something!

Agree! Auto-brightness for me has always been an annoyance more than anything else. My L920 has been trouble free since the beginning.

I have the brightness setting to medium.. everytime i turn off and power the phone back on its very bright and i have to go to settings which is still on medium, put it to low then back to medium. 
I have all settings off that dims the brightness or battery saver.. anything like that. 
Just tried this weird fix and it didnt work

This has nothing to do with Portico... I'm still stuck on 9903 and I have this problem as well. I think it has to do with the latest display&touchscreen settings update

My problem with the auto setting is actually different. Since the first day I purchased the 920 the auto setting causes the brightness to be so low that the screen is barely readable even in a completely dark room. I've commented on this in the forum before. The screen actually seemed to be slightly darker after the update yesterday. I've gotten used to just turning auto off and using medium brightness.

Hey, I got quoted in a front-page article, rad!
I just did the restart-in-pitch-black-room-and-slide-up-lock-screen thing (yay for server rooms).  I'll report back if the problem shows up again.


But a dark room guarantees coverage as the ambient light sensor is very difficult to see through the plastic, meaning a lot of people may not know where it even is to cover it. Don't want to get false positives.

Its probably important for the device to be brought out of suspension while completely dark to initialize the proper calibration.

I seriously need to start proof reading my comments . I made like 5 grammatical errors which I'm blaming on wp8 retarded auto correct. I was the one who commented about the bat signal brightness. And my phone still does it even after going into a pitch black room and doing what he said. It happens everytime I turn the phone on and off. My phone get so bright it hurt looking at the screen :).

Why take it to a room, just cover the light sensor anywhere. Not that its related, but this issue exists on my Surface as well. On the other hand, my 920 with Portico is fine. I never had the problem on my phone.

I found the screen turns off and locks when listening to audio via Bluetooth in my car, something it never did before nor did wp7. Annoying when I'm driving.

My suggestion for future is not to install any new phone updates right away as soon as they are released..wait a bit until all issues have been addressed..I currently have not installed the update (portico) for my phone yet..waiting until any and all issues have been addressed before updating to the new Portico update..by doing this, this may save me from having any issues..hope this works for me

On the other hand, I and many others updated and have had no issues. This may be a limited set of users. For me, it seems to have fixed all bluetooth/reset/stability issues, so thank goodness i'm not sitting here waiting for every user to give their all clear (which will never happen btw) before installing.

Which is way we are thankful for those taking the plunge and updating immediately!  Those of you who do are the troubleshooters and your input is what makes the fixes possible.  And your feedback informs those who are a little gun shy about updating, enough so that a decision can be made about whether or not we will pull the trigger.

I disagree, worst case u can roll back/reset (I assume) my phone definitely seems more stable after the update and I do not have the sensor issues mentioned here.

A even better suggestion to to wait for at least 6 months before buying a newly launched phone. This way we will be saving lot of hazles of visiting online forums for help and wasting lot of time for no fault of us.

If you wait about two years you'll have all the fixes and no worry about new upgrades. No need to spend all your time on the forums getting work-arounds.

Or you could just cover the top portion of the phone where the AT&T/Nokia logos are with your hand and then turn the phone on...

Yes, but people are dumb. Some will do that and won't cover it all up or let light in and then say "it didn't work". You need to take the dumb out the equation, hence the no-light recommendation.

Or rather, which method has less room for user error? Exactly. 

Very true, but in this case, I don't think the "fix" actually works.
Kind of on topic, but as someone else in this thread mentioned, this might not be related to Portico, but rather the last display + touch update. They came out right around the same time.

I don't think it has anything to do with Portico but it is either Display + Touch or firmware.

Traditionally, firmware from OEMs control the ambient light sensor and calibration, but with Display + Touch, I'm not sure how "deep" it goes in allowing changes to that function.

Just for curiosity sake. For those who are having problems, do you have a screen protector over the sensor or could it be dust related? Obviously with the new update its the first possibility, but could the sensors sensitivity have been updated/changed enough that a previously unobtrusive screen shield is now affecting it? I only ask because I do not have this issue with my updated Lumia 920 from Rogers. Just trying to help by pointing out possible variables.

I've been having a rather annoying problem (though not sure problem is the right word). Whenever i unplug my 920 from charging (even wireless) it plays a system noise, however my ringer is definitely off. In fact, I never EVER have my ringer on, and I'll be honest, this one really bugs the crap out of me. Do any of you have this strange problem?

It's a notification that it's been removed from charging. It was added with one of the updates a few weeks ago, can't recall which. I can see why it annoys some folks, but it's not a bother for me.

I think it is really sad that the recommended course of action is for Lumia users to go hide in a closet. So much ammunition for Android and iPhone users.
Second, I will try it because it is annoying and the screen seems to get too dim in dark rooms. Hard to read.
Also, has anyone noticed the capacitive button not lighting up when this is happening? I had that problem last night.

This isn't a Windows Phone thing but rather a common issue with ambient light sensors all around, on any device. Lots of Samsung phones (Android too) have calibration problems and if you hang around our forums or Android Central's, you'll see things like this pop up all the time.

Another thing I'd say is our forum ratio compared to AC's is rather low because Windows Phones as a whole (and even the Lumia 920 specifically) have a lot less bugs and quirks than the Android platform.

Shouldn't the exact opposite also do the trick? (E.g. holding it under a bright light before resuming from stand-by?)

Same issue on, he ATIV S which is running this update. I'll try out the fix tonight. I've had it set to medium brightness since i got it because of this bug. Thanks for the fix.

Maybe that's why T-Mobile postponed their update....hummmm! I have a HTC 8x and after update I haven't had that problem anymore..

Update casued no issues for my L920. Hope the next update includes the ability to disable toast notifications for SMS messages. 

Why even have a phone if you don't want to be alerted to one of its most basic features. I get that choice is nice, but I suspect you are in the smallest of minorities.

You can turn off SMS/text IM alerts under sound settings already. What would be great is not to turn off SMS alerts, but turn off alerts for Messenger/Facebook chat individually. Sometimes it does get annoying when you're in a group Windows Live Messenger conversation and it keeps alerting you every second.

He/she specifically states that TOAST notifications should be disabled which has nothing to do with sound alerts.

Pardon my ignorance, but I don't get steps 4 (?) and 5 (Profit) in the fix. What exactly am I supposed to do after sliding the lock screen up? I haven't experienced the brightness bug, but I figured it wouldn't hurt to calibrate the ambient sensor anyway. For me, I'm finding the screen is now generally too dim on the auto brightness setting, so I've turned that off and set the brightness to Medium. I'm curious to see if auto brightness wouldn't be so dim after calibration.

There's nothing to do. That's it. You're just letting the ambient light sensor kick in to see darkness. The ALS takes a reading everytime you unlock the device.

I had this issue, did the backroom trick and its seemed to have fixed it!  at least has worked correctly for the last 15 mins which it was not prior to doing the blackroom trick.  Thanks!  Hopefully it will stick. 

Worked for me. Looked silly running into my closet like Tom Cruise to do this but it worked. I barely noticed it until I read the post too so thanks.

My 920's screen has been going crazy ever since I updated it. The screen goes so bright that on the homescreen the black background goes grey. The trick didn't work either.

Update, the dark room trick didnt stick.  about 30 mins after got back on my phone and brightness going up and down.  

The blacks looks horrible on high. When I pick up my Omnia7 nowdays I kind of cringe looking at my 920 screen, WP ui looks so good with amoled.

It seems the dark room trick worked for me as I haven't had the issue since, but we shall see once I get home.

Why go in a pitch black room? Just remain in the dimly lit room, cover the sensor with your thumb, and reboot. That's what I did last night when the error occurred. Covering the sense eliminates any light emitted by the phone also. It worked last night.

Ok, tried the " fix " this afternoon at lunch, went into bathroom and turned off light, slid lock screen then relocked screen and repeated then turned light on, screen seemed to flicker briefly then adjusted to normal, reset auto brightness to on, and I can happily report I have not had any more occurrence of the bug ( knock on wood) thanks for the tip WPCENTRAL

I have this problem as well! Display brightness worked perfectly before...now it's a complete mess! Can't wait for any update (MS or Nokia) to solve this issue!

The problem is auto brightness actually worked. It was the first smartphone I've used where the brightness was adjusted perfectly. Its a shame :( but yes i had to turn it off...

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The admins really should delete your post.
Sameless advertising is NOT the reason to be posting here in the forums.

My 920 was looking washed out in sunlight prior to the update and then looked perfect again. However it started doing as described in this article so I did the recalibration and now it washes out in sunlight again. Any suggestions to fix both problems?

I wonder if any leadership from Microsoft and Nokia reads the forum posts. Love my Lumia 920 but these little bugs really need to be fixed ASAP if they want to keep the faithful... Won't hurt my Nokia stock prices either... :)

I have a Lumia920 and am also having this issue. I tried the "fix" to no avail. I don't know if this is a wp8 issue or Nokia issue, but like everybody else I spent a lot of money on this device and demand a fix immediately! This is a very annoying issue and quite frankly unacceptable.

Instead of going through all the trouble of finding a pitch black room, how about just covering the sensor! or turning it on in your pocket.....  The lack of logic scares me sometimes.

I don't have a 920 (822 ov VZ) but one thing I would try myself would be to backup my data and do a factory reset on the phone to eliminate the possibility of corrupt or conflicting settings or software. Phone carriers would do this anyway. If it still does this, I'd expect it's HW related and seek a replacement phone.

If the bug is really that annoying try just going into the phone settings and setting the screen to low, medium or high.  Presto, no more screen fluctuations.  

You just can't adjust it manually everytime you switch environments: LOW brightness setting will not be enough outdoors in sunny (or snowy) places, while MEDIUM and HIGH are way too much at night. Turning off features just to make a phone work is not an acceptable solution.

I am having a different issue, I set my phone to low brightness but after a reboot the phone is showing high brightness, I have to cycle levels again for it to be low again.

Ok so I have the 920 and I have this issue. What I seem to notice, and it maybe due to my specific Otterbox case, that another factor affecting the screen brightness is that the sensors are picking up reflected light bouncing off of the wall of the phone case. My Otterbox is designed to have the phone recessed so when dropped nothing makes contact with the screen causing it to break/crack. This creates a walled affect around the edge of the phone. When the lighting in the room causes the screen brightness to increase there is residual light that is picked up by the sensor causing the phone to think the room is brighter then it really is causing the screen to dim. Then it picks up the light in the room and attempts to brighten up the screen as it believes the room is bright enough. This is an annoying cycle that is hard to break! Any thoughts?

I downloaded nokia care suite and installed, I downloaded the latest version ...
I started the installation of the instructions and installed the same ... It says that it is in offline mode and it is necessary to disconnect from online, I think the computer ...
[XDA News] [How To] Download and flash all WP8 Nokia Lumia Stock ROM - xda-developers
After connecting, I did calibraciju everything I could, and we were offered ...
ALS calibration is required to have another similar device and both must be in test mode (I have L920 and L1020), both of which are in test mode and I did a calibration on the second L920.
I do not know if I should, I turned off the light in the room and did the calibration according to another device.
Nokia Care has requested that the devices are next to each other in order to give it more like reading ...
I do not know if I was able to do anything to improve ... I'll just see ... Sorry for my english (google translate... )