Apple Will Fix the iPhone 8/8 Plus/X Auto Brightness Issue in iOS 12

We all know that the Apple has disabled the iPhone 8/8 Plus/X auto brightness function after replacing the LCD screen or sensor flex cable in iOS 11. Even with the OEM screen and sensor cable, the auto brightness still doesn’t work.

iOS 12

Why auto brightness not working

When this issue was reported, we ETrade Supply did some tests for possible reasons. More about our testing result please visit this article: The Way to Fix iPhone 8/8 Plus Screen Ambient Light Sensor Disabled.

The reason why this happens is that there is a chip in each iPhone screen and sensor cable, it records the unique ID information of the part. When the device was booting up, the phone will check the information in the screen and sensor cable. If the screen or sensor cable information doesn’t match to the motherboard, the auto brightness function fails to work.

Chip on iPhone parts

Upgrade iOS 11 to iOS 12 beta 2

Apple launched the iOS 12 beta 2 on June 19, it is proved that it has fixed the iPhone 8/8 Plus/X auto brightness disabled issue. For those iPhone users who want to fix the auto brightness not working issue, just upgrade the iOS system to iOS 12 beta 2. Below are how to upgrade the device system to iOS 12 beta 2.

  • 1. Back up your device with iTunes to prevent any unexpected data loss.
  • 2. Visit with your Safari and click Download.
  • 3. Enter the Apple ID and password to log in.
  • 4. Install the iOS beta software profile and restart the device.
  • 5. Go to Settings>>General>>Software Update, click Download and Install.
  • 6. Enter the password and agree to the terms.
  • 7. Once you confirmed, the device will download and install the iOS 12 beta 2.

install iOS 12

After the installing, you can get a device with iOS 12 and the auto brightness not working issue is fixed.

Downgrade the iOS 12 to iOS 11

If you don’t like to use the iOS 12? Just downgrade the iOS 12 to iOS 11. To downgrade iPhone system, please refer to “How to downgrade iPhone iOS system” in How to Fix iPhone Battery Drains Fast with iOS 11.4.

As the iOS 12 beta 2 is a beta iOS system, we can’t make sure Apple will still fix the auto brightness not working issue in iOS 12 public. So, we will keep an eye on it and update it to you at the first time.

(Update: Apple released the iOS 12 system on Sep.18th, and we have upgraded the iPhone 8 and iPhone X to the iOS 12. The test result is that the Auto-brightness function is fixed by the iOS 12. If you replace an aftermarket LCD screen or sensor cable with ear speaker, the  ALS will work normally. Note: If you replace the sensor cable with ear speaker, the ALS will work but you will lose the Face ID. )

Any questions about this article, welcome to comment below. Also, if you have other questions about iPhone repair, leave a comment below too.

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  1. BY Tim

    Is the True Tone function still broken with aftermarket screens (mid-2019) and iOS 12? Thank you

  2. BY What about true tone

    Auto brightness came back after iOS 12 upgrade, but true tone opion disappeared, any suggestions.

    • BY kaye

      Hi sir, there is no method to solve the true tone issues in the market so far.

  3. BY Jelina

    I dont necessarily agree with the statement above. I had my phone replaced through AT&T insurance program, as I had a pin sized crack and they said I wouldn’t be able to trade it in.

    The auto-brightness didn’t work after replacement but the true tone did. I just upgraded to iOS 12 today and now neither work.

    • BY kaye

      Hi Jelina, we have tested the auto-brightness function with the iOS 12, it works well with aftermarket screen.

  4. BY Piel Sarmiento

    iOS 12 beta fixed auto brightness but now True Tone disappeared.

    True Tone was working fine in iOS 11.4.1 but of course auto brightness was disabled. Have you found a fix yet?

    • BY kaye

      Hi Piel, the True Tone is disabled after screen repair. If you don’t want to miss the True Tone function, you should repair your phone in Apple Store, there is no other ways to fix this issue from now on. The iOS 12 BETA only fixed the auto brightness, but we ETrade Supply will still keep a eyes on this issue.


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