Severe brightness issue (screen largely unusable)

jptiger

Senior Member
Jul 23, 2011
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Hi all, I have a problem with my stock T-Mobile US S9. A few months ago this weird thing happened where if I turned on my screen immediately after it turned itself off, only the top few lines would be visible. The whole screen would take input, but you could only see a little below the status bar, maybe. If I waited a bit and then turned the screen on, it would work normally, with the whole screen visible and looking fine.

It's gotten progressively worse to the point where this happens most of the time I turn the screen on. However, I've found two workarounds:

1) My Always On Display is set to turn on when I tap the phone. If I do that, the AOD works as normal, and if I then turn on the phone screen the phone screen works fine. This only works when Always on display is set to turn on on tap. It does not work if AOD is set to always be on.

2) If, when my screen is glitching out I hold the screen up to a reeaally bright light (like inches from a lightbulb), the rest of the screen turns on. It's weirdly green tinted and kind of stuttery.

Turning off automatic brightness does not fix this issue. If tried booting in safe mode and even factory resetting the phone. Issue still persists, including on screens like when the phone enters recovery mode.

The fact that I can get the screen working normally using workaround #1 makes me think this is a software issue, but the fact that it happens on the recovery screen makes me think it's pretty low-level. Any ideas? Anyone else had a similar issue?
 

jptiger

Senior Member
Jul 23, 2011
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I gave Samsung tech support a call and the level 1 tech I spoke with seemed to think that it was a software issue and that I should bring it in to be looked at by a technician. I'm in Maine at the moment and there's no Samsung or UBreakIFix stores within two hours, so she suggested taking it to Best Buy to look at. Not amazingly helpful or surprising.

If it's a software issue though... I mean this is my fourth Android phone and I've rooted and flashed ROMs on all the previous phones anyway. I don't want to lose Samsung Pay, so I'd rather not unlock the bootloader, but is there a way to flash the stock operating system or something? The exact model number is SM-G960U
 

blackhawk

Senior Member
Jun 23, 2020
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It's a firmware or hardware issue not software as a reload* would have fixed it.
The firmware has been corrupted (needs reflashed) or there's been a hardware failure.
Best to send it in for repair or take it the a Samsung Experience Center as they can reflash the stock rom and have advanced diagnostic tools.

*make sure all system apks are running on factory load and have not been updated after the reload.
Updates, destroyers of worlds...
 
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jptiger

Senior Member
Jul 23, 2011
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It's a firmware or hardware issue not software as a reload* would have fixed it.
The firmware has been corrupted (needs reflashed) or there's been a hardware failure.
Best to send it in for repair or take it the a Samsung Experience Center as they can reflash the stock rom and have advanced diagnostic tools.
If that’s really necessary I’ll do it. But the closest place is out of state and when I called them said it would take 4 hours just to do a diagnostic. That plus the round trip... if there’s a way I can save some time, I’d like to.

For example, if one possibility is a stock firmware reflash, that’s something I’ve never done before on a Samsung device, but not very different from things I feel comfortable doing. I've flashed roms and rooted many android devices in the past. From a preliminary search , it looks like there's even a leaked tool online to do so from Samsung called Odin and that I just need to find the latest SM-G960U image with the right "csc" code for my carrier (I think TMB for T Mobile US). What would be even better is if one of those diagnostic tools you mentioned leaked the same way that Odin did.

Any recommendations on either diagnostic software or firmware reflashing? Or would you strongly advise leaving that kind of thing alone? I would like to still use things like Samsung Pay at the end of all this.
 
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blackhawk

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Jun 23, 2020
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If that’s really necessary I’ll do it. But the closest place is out of state and when I called them said it would take 4 hours just to do a diagnostic. That plus the round trip... if there’s a way I can save some time, I’d like to.

For example, if one possibility is a stock firmware reflash, that’s something I’ve never done before on a Samsung device, but not very different from things I feel comfortable doing. I've flashed roms and rooted many android devices in the past. From a preliminary search , it looks like there's even a leaked tool online to do so from Samsung called Odin and that I just need to find the latest SM-G960U image with the right "csc" code for my carrier (I think TMB for T Mobile US). What would be even better is if one of those diagnostic tools you mentioned leaked the same way that Odin did.

Any recommendations on either diagnostic software or firmware reflashing? Or would you strongly advise leaving that kind of thing alone? I would like to still use things like Samsung Pay at the end of all this.
If it's under warranty let Samsung deal with it. A good tech with experience is invaluable.
Rather then waste time the extra ride might end up being the easiest solution. You could also next or 2nd day it to the center and back, make sure it's insured and packaged well.
 

jptiger

Senior Member
Jul 23, 2011
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If it's under warranty let Samsung deal with it. A good tech with experience is invaluable.
Rather then waste time the extra ride might end up being the easiest solution. You could also next or 2nd day it to the center and back, make sure it's insured and packaged well.
That makes complete sense for something under warranty, but unfortunately my phone isn't. The S9 is about three years old now, and the Samsung rep was quick to tell me that the device was no longer covered. It looks like a mail-in repair service would cost about $175, which I'm theoretically willing to pay, but not if I can just handle on my own for free.
 
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blackhawk

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Jun 23, 2020
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That makes complete sense for something under warranty, but unfortunately my phone isn't. The S9 is about three years old now, and the Samsung rep was quick to tell me that the device was no longer covered. It looks like a mail-in repair service would cost about $175, which I'm theoretically willing to pay, but not if I can just handle on my own for free.
In that case you have nothing to lose by reflashing it. Hopefully that gets it.
Otherwise it be hardware... probably a good chance this actually the cause.

The good news is the 9's are available for a couple hundred in good condition if need be.
I was considering getting the 9 as a second phone (have the 10+) as the 10+'s haven't come down much in price.
Samsung current lineup sucks.
 
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jptiger

Senior Member
Jul 23, 2011
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Huh. Well, before reflashing, I tried something I found other people suggesting for a related problem: https://eu.community.samsung.com/t5...t-bars-black-screen-issue/td-p/1745470/page/7

It's an app called OLED Saver. It's not perfect, the screen still has an odd green tint to it unless I use one of the tricks I was describing above. But I no longer have the issue where most of the screen isn't visible.

I might try reflashing anyway, will post results if I do.
 
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jptiger

Senior Member
Jul 23, 2011
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Yeah, no joy. Reflashed by downloading the latest firmware using Frija for SM-G960U with TMB as the CSC, and flashed using Odin v3.13.3. If anything the problem is slightly worse now, but OLED Saver still mostly seems to fix it. I guess it's just a hardware issue with a weird software workaround...
 
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linoux

Member
Mar 31, 2016
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Same type of brightness problem here as you describe, on my new S9 (G960U) - - Model starqltesq - CSS XAA

The product is under guarantee, but as it is imported from Hongkong to France, I don't have accesss to the Samsung local representatives and have probably to send it back to Hongkong ...

I will keep you updated if I learn something about the problem and the solution ....
 

Bhonka

Senior Member
Jul 14, 2010
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Wiping the cache partition stopped this happening for me for around 24 hours but it came back this morning. On the Note9 forums someone posted that setting animations to .5 in dev options fixes this. I will try it.
 

blackhawk

Senior Member
Jun 23, 2020
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Wiping the cache partition stopped this happening for me for around 24 hours but it came back this morning. On the Note9 forums someone posted that setting animations to .5 in dev options fixes this. I will try it.
Disable animations instead. It wastes resources. Personally I like seeing a fast, snappy OS do it's thing with no middle man needed. Lol, you end up waiting for the animations rather than the OS.
 
Dec 18, 2012
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I've heard of people flashing custom roms and that resolved the issue permenetly, but can't find anyone willing to give some real feedback. I posted a topic asking this question, but haven't gotten any replies..