Galaxy S7 won’t turn on and stuck in black screen after rooting, showing green lines

Today’s #GalaxyS7 troubleshooting article addresses two cases wherein the device’s screen turns black and appears not to turn on anymore. The circumstances in these two cases are different but the solutions may be the same. Don’t forget, black screen issues on S7 phones usually occurs due to hardware damage so if software solutions won’t work, repair may be necessary to address them.

Before we proceed, we want to remind you that if you are looking for solutions to your own #Android issue, you can contact us by using the link provided at the bottom of this page. When describing your issue, please be as detailed as possible so we can easily pinpoint a relevant solution. If you can, kindly include the exact error messages you are getting to give us an idea where to start. If you have already tried some troubleshooting steps before emailing us, make sure to mention them so we can skip them in our answers.

Problem 1: Galaxy S7 won’t turn on and stuck in black screen after rooting

Hey I’m really i’ve been reading for hours and can’t find a resolution. So I have a Samsung galaxy S7 and I have attempted to Root and something went wrong I will turn my phone on and it will display a black screen that says Samsung galaxy but up to top left hand side it says kernel seandroid enforcing or something like that. that screen will display for about 2 seconds then it will go fully black then it will come back and vibrate. I can put the phone into download mode and recovery mode. in recovery mode I have cleared the cache partition and have tried to factory it but when I press reboot I can the Samsung screen for 2 seconds with the red text again. I was looking for a rom or something like that for my phone but cannot find any for my specific one. Any help is very appreciated.  The thing if it helps g930fxxu1dqhc and I am with Telstra. — Bodie R

Solution: Hi Bodie. Rooting is basically tampering with your device’s software so it’s a high risk procedure and can potentially cause permanent software issue. Samsung does not recommend rooting because it can open the system for unwanted intrusion but also because doing so may lead to the problem you’re experiencing right now. Because rooting errors are usually specific to the rooting software and disposition of the device, there’s often no exact way to solve a particular case. The best that you can do, aside from doing a factory reset thru Recovery Mode, is by flashing stock bootloader and/or firmware.

Below are the general steps on how to flash a bootloader of a Samsung device. Exact steps may be slightly different for your particular phone model so we highly suggest that you do some digging to know how to flash the stock bootloader to your S7. Make sure that you flash the bootloader before flashing stock firmware. By stock, we mean the original firmware that came with your S7 when you unboxed it, or the exact Android version or firmware before you modified rooted or flashed a custom ROM. Taking note of this firmware version is a necessary precaution before tampering with the software. We hope you did this. Otherwise, you have to spend more time researching what the exact version of your phone model was using. Keep in mind that using an incorrect firmware version can permanently brick a device so unless you can afford to just get a new replacement, you need to be careful when flashing or rooting.

  1. Look for the correct firmware for your phone model and download it. Make sure that you select the right one. It should be the same exact firmware that ran previously on your device. We assume that you list down the firmware version somewhere. If you did not take note of it before, there’s a chance that you may pick the wrong one. As you may know now, using an incorrect firmware can cause complications so good luck with that.
  2. Let’s now say that you have identified the correct firmware. You then want to download it to your computer. The firmware file should have a bunch of files in it like AP_, BL_, CSC_, etc.
  3. Look for the file that starts with a label BL; this should be the corresponding bootloader file for this firmware. Once you’ve identified the bootloader file, copy it to your computer’s desktop or to any other folder that you can easily access.
  4. Proceed with the rest of the flashing procedure using the Odin program.
  5. In Odin, click on the BL tab and make sure to use the bootloader file you’ve identified earlier.
  6. Now, make sure that the “Device Added” status and its “ID:COM box” has turned blue before hitting the START button. This will initiate the flashing of your phone’s bootloader.
  7. Restart the phone once the procedure is finished.

As mentioned above, the steps on how to flash a bootloader may not be the exact way to flash the bootloader of your S7. Make sure that you consult other guides on how to do it.

Flashing your S7’s firmware should follow a similar set of steps as provided above. Be sure to again research more about the topic before doing it to avoid causing more problems.

Problem 2:  Galaxy S7 screen is black and showing green lines when device is on

Hello. I am getting an issue similar to “the black screen of death”. The only difference is, all of the buttons and functions are still responsive. I also dropped my phone a very long time ago causing the right side of the screen to have permanent lines show up unless the phone is turned off. I noticed that if I try to turn my phone on, these lines still show up. And if I swipe my screen, the phone still vibrates when I tap a button to input my password. Yet the screen, aside from those green lines, stay black. I’ve tried force resetting my phone but it didn’t work. Also, my phone is a samsung galaxy s7 and I haven’t seen any way to remove the battery from the device. Also, I may be wrong about my android version, but as far as I know it is on oreo. — Dylan Grems

Solution: Hi Dylan. The screen assembly of your Galaxy S7 is composed of three major parts — monitor, digitizer, and digitizer flex cable. The monitor is the part that displays the images you see. It’s similar to the monitor on your computer, only in a much smaller scale. The digitizer is a thin layer on top of the monitor that captures your finger touches so they can be interpreted by your phone’s system. The signals from the digitizer are transmitted to the logic board via the flex cable. So, in essence, the screen assembly can only work normally if all the three parts are working properly.

In your case, we think there’s a problem with the monitor. This is the reason why the screen remains black though the phone still appears to take your touches. The monitor may have been damaged causing it to being unable to display images.

To see if the problem is being caused by an app or software bug, try these two possible solutions:

  • run the phone on safe mode
  • factory reset via Recovery Mode

In order to restart your S7 to safe mode, follow these steps:

  1. Turn your Galaxy S7 off.
  2. Press and hold the Power button.
  3. Once the ‘Samsung Galaxy S7’ logo appears, release the Power key and immediately press and hold the Volume Down button.
  4. Continue holding the button until the phone finishes rebooting.
  5. Once you see the text “Safe mode” at the bottom left corner of the screen, release the Volume Down button.

If your S7 screen turns on and works normally on safe mode, that means an app is causing the screen to not work.

If the problem remains in safe mode, or when nothing happens when you boot your S7 to safe mode, try to restart it to Recovery Mode. In this mode, you can try to clear the cache partition or perform a factory reset. Here are the steps to boot your S7 to Recovery Mode:

  1. Turn off your Samsung Galaxy S7.
  2. Press and then hold the Home and Volume UP keys, then press and hold the Power key.
  3. When the Samsung Galaxy S7 shows on the screen, release the Power key but continue holding the Home and Volume Up keys.
  4. When the Android logo shows, you may release both keys and leave the phone be for about 30 to 60 seconds.
  5. If your screen works, use the Volume Down key, navigate through the options and highlight ‘wipe data / factory reset’ or ‘wipe cache partition.’
  6. Once highlighted, you may press the Power key to select it.

Just like in safe mode, if the screen works only when you boot to recovery mode, that means  there’s a software issue behind the trouble. Make sure to factory reset your S7 to fix the issue.

If the S7 screen remains black after attempting to boot your device to safe mode or recovery mode, that means you have a bad hardware. Contact Samsung so they can repair the device.

 


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