How to fix your Samsung Galaxy S9 that keeps rebooting after a firmware update (easy steps)

Firmware updates are supposed to fix problems but there are times when things go the other way and such is the case with some of our readers that own the Samsung Galaxy S9. According to some their devices started to reboot randomly and/or frequently shortly after the most recent firmware update. Could this be an issue with the firmware itself? Or could it be just a minor issue due to incompatibility of some services and apps with the new system. We will have to find out which is which.

In this post, I will walk you through in troubleshooting your Galaxy S9 that started acting up after an update. We will consider every possibility and rule them out one by one until we can determine what the problem is and do something about it. So, if you’re one of the owners of this device, or any Android phone for that matter, and are currently bugged by a similar problem, continue reading as this article may be able to help you one way or another.

Before anything else, if you have other issues with your device, try to browse through our troubleshooting page as we’ve already addressed several issues with this device. Odds are that we’ve already published a post that tackles similar problems. Try finding issues that have similar symptoms with what you currently have and feel free to use the solutions we’ve suggested. If they don’t work for you or if you still need our help, then fill up our questionnaire and hit submit to contact us.

What to do with Galaxy S9 that keeps rebooting after an update


When it comes to reboot issues, they’re often due to a firmware problem and considering the fact that, in this case, they started after a firmware update, it validates our suspicion. But then we will try to systematically rule out each possibility. Here’s what you should do about it:

First solution: User your phone in Safe Mode

You should still be able to use your phone even in safe mode as pre-installed applications will still run. The purpose of this steps is to rule out the possibility that this problem is due to third-party applications. It doesn’t matter why but if it’s caused by the app you downloaded from the Play Store manually, then it’s pretty easy to fix. Don’t worry though, none of your files and data will be deleted if you started your phone up in safe mode:

  1. Turn the device off.
  2. Press and hold the Power key past the model name screen appearing on the screen.
  3. When SAMSUNG appears on the screen, release the Power key.
  4. Immediately after releasing the Power key, press and hold the Volume downkey.
  5. Continue to hold the Volume down key until the device finishes restarting.
  6. When Safe mode appears in the bottom left corner of the screen, release the Volume down key.

Once you’ve successfully started your device up in this mode, try using it like you always do (minus the third-party apps) and wait to know if it would still reboot by itself or not. If the reboots disappear, then it means there’s a third-party app that’s causing or triggering the problem. Find out which of your apps is the culprit and then uninstall it. Here’s how you do that:

  1. From the Home screen, swipe up on an empty spot to open the Apps tray.
  2. Tap Settings > Apps.
  3. Tap the desired application in the default list.
  4. To display preinstalled apps, tap Menu > Show system apps.
  5. Tap UNINSTALL > OK.

However, if the phone still reboots while in safe mode, then we have to do after the firmware as that might be where the issue lies.

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Second solution: Delete the system cache

Considering the fact that this problem started after a firmware update, there’s a chance that it’s just due to some corrupt cached files. Caches may become obsolete when a new firmware is installed and they need to be replaced and inorder to do that, you have to delete them. So, you will have to wipe off the contents of the cache partition so that the old cache will be replaced with a new one and here’s how you do it:

  1. Turn off the device.
  2. Press and hold the Volume Up key and the Bixby key, then press and hold the Power key.
  3. When the Android logo displays, release all three keys.
  4. An ‘Installing system update’ message will show for 30 – 60 seconds before the Android system recovery menu options appear.
  5. Press the Volume down key several times to highlight wipe cache partition.
  6. Press Power key to select.
  7. Press the Volume down key to highlight yes, them and press the Power key to select.
  8. When the wipe cache partition is complete, Reboot system now is highlighted.
  9. Press the Power key to restart the device.

After doing this, take time observing your phone closely to know if the problem continues and if it still does, then you have no other choice but to do the next procedure.

Third solution: Backup important files and do the Master Reset

After the first two procedures and your phone still reboots by itself, then you will have to give it a fresh start by resetting it. If it were just a minor firmware issue and if the update was properly or completely downloaded and installed, then this is the procedure you need to do to fix it. The update will remain but you will need to make a backup of your important files and data as they will be deleted and you may not be able to restore them after that. Backup as many files and data as you can and when you’re finished, follow these steps to reset your device:

  1. Turn off the device.
  2. Press and hold the Volume Up key and the Bixby key, then press and hold the Power key.
  3. When the green Android logo displays, release all keys (‘Installing system update’ will show for about 30 – 60 seconds before showing the Android system recovery menu options).
  4. Press the Volume down key several times to highlight ‘wipe data / factory reset’.
  5. Press Power button to select.
  6. Press the Volume down key until ‘Yes — delete all user data’ is highlighted.
  7. Press Power button to select and start the master reset.
  8. When the master reset is complete, ‘Reboot system now’ is highlighted.
  9. Press the Power key to restart the device.

I hope that this troubleshooting guide can help you fix your Galaxy S9 that keeps on rebooting by itself. If you have other concerns you want to share with us, feel free to contact us or leave a comment below.

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