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Galaxy S7 won’t boot up, only restarts to Download mode, won’t connect to mobile network, other issues

The #GalaxyS7 has been with us for some time now so we expect that there will be an ever increasing number of issues our community will report to us. As usual, we bring you this post that handles some of the reported S7 problems so far.

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.

Below are specific topics we’re bringing for you today:

Problem 1: Galaxy S7 “invalid sim card” error, won’t charge, won’t turn on

Hello. Starting yesterday, I have been having two main issues with my phone but I am not sure if they are related.

1) My phone will periodically give me an “invalid sim card” message. During this time, I obviously cannot make and calls or send/receive texts. If I restarted the phone, it would work for 5-10 minutes before giving the “invalid sim card” message again. The sim card issue lasted all of yesterday but eventually subsided at night.

2) Although the first issue passed, I now have a larger issue. My phone will not charge. When I plugged it in last night (had around 20% charge left) the phone would not show the lightning bolt on the battery icon and would turn off. Even after turning it back on and seeing that there was about 20% charge, if I plugged the charger into the phone, the phone would almost immediately turn off. I tried this a few more times and, after a while, when I would plug in the charger, the screen would go black and two small, white “x’s” would pulse at the bottom of the screen before the phone was completely unresponsive again.

I tried using multiple different chargers. I also tested the chargers on other products to make sure that they were working. Now, my phone battery is dead and when I plug in the charger the large gray icon of a battery with white lightning bolt shows up in the middle of the screen but nothing else– no charge percentage or anything. When I try to turn the phone on, it just turns back off or doesn’t respond. I have tried the “power-volume down-home button” reset to no avail, either.

 Any advice would be greatly appreciated, as this issue came completely out of the blue. Roland P.S. I’m not sure what version of Android is running, so I just put “other.” — Rdewgard

Solution: Hi Rdewgard. The SIM card issue you had was probably due to a network glitch. It can also be caused by a broken SIM card slot so if it returns in the future, these are the order of things that you must do:

  1. Check if SIM card works fine on another device.
  2. Replace SIM card if it’s defective.
  3. Do a factory reset to check if it’s a software problem.
  4. If nothing will change after a factory reset, bad hardware must be to blame. Get a phone replacement.

For your second issue, the most likely cause is hardware malfunction, particularly the charging port. To check, do a factory reset first and observe what happens. Here’s how:

  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. Using the Volume Down key, navigate through the options and highlight ‘wipe data / factory reset.’
  6. Once highlighted, you may press the Power key to select it.
  7. Now highlight the option ‘Yes — delete all user data’ using the Volume Down key and press the Power button to select it.
  8. Wait until your phone is finished doing the Master Reset. Once completed, highlight ‘Reboot system now’ and press the Power key.
  9. The phone will now reboot longer than usual.

As mentioned, we suspect that the phone’s charging port is busted. If factory reset won’t fix the charging problem, or if you won’t be able to turn the phone on at all, stop looking for software solutions. An issue like this can’t be fixed on your end. Let a professional check the status of the hardware so you’ll be advised whether you need to have the phone repaired or replaced.

Problem 2: Galaxy S7 screen is black and won’t turn on

I plugged my phone in last night and I am still getting alerts for email or text, but the screen is black, so I cannot see anything. Is there anything you can do? Thank you! — Sarah

Solution: Hi Sarah. An issue like this does not happen overnight so there might be a preceding event that caused it. Was the phone physically impacted, dropped, or exposed to elements before? Any of these three can damage the screen permanently so the only course of action for you is to have the phone repaired or replaced.

If you don’t think bad hardware is to blame though, a possible reason can a software glitch. To check, try to see first if you’ll be able to start the device to any of these alternate modes:

Boot in Recovery mode:

  1. Charge the phone for at least 30 minutes.
  2. Press and then hold the Home and Volume UP keys, then press and hold the Power key.
  3. When the Samsung Galaxy logo 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. Using the Volume Down key, navigate through the options and highlight ‘wipe cache partition.’
  6. You can either wipe the cache partition or do a factory reset when in this mode.

Boot in Download Mode:

  1. Charge the phone for at least 30 minutes.
  2. Press and then hold the Home and Volume DOWN keys, then press and hold the Power key.
  3. When the Samsung Galaxy logo shows on the screen, release the Power key but continue holding the Home and Volume DOWN keys.
  4. Wait until the Download screen appears.
  5. If you can boot the phone in download mode but not in other modes, that means that your only way out may be to flash a stock or custom firmware.
  6. Use Google to look for a guide on how to do it.

Boot in safe mode:

  1. Charge the phone for at least 30 minutes.
  2. Press and hold the Power button.
  3. Once the Samsung Galaxy 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.
  6. The only difference of safe mode from normal mode is that the former prevents third party apps from running. If you can boot the phone in safe mode but not in normal mode, uninstall all apps until the issue (that prevents you from booting normally) is eliminated.

Problem 3: Galaxy S7 keeps rebooting, won’t turn back on, after accidental drop

S7 dropped in March 17. Worked for a week then shut down 10 min into a charge. It has 38% battery at present when I can turn it on which has been only twice through a normal one press of the power button , otherwise it is completely unresponsive, to any boot sequence. fails to charge at this point. After finally getting it to turn on (big surprise when it did) I transferred 5GB of pictures. (So relieved I got them ) there after I maintained a charge from laptop only to have it go to sleep then suddenly shutdown (or crash) . Reconnected charger , it starts charging ( shows an empty battery) then slowly shows correct valve at 38%. Seconds later it’s all gone again. Normal start up then instant reboot. Then nothing. Its unresponsive again. Spent hours trying to turn on. — Daphpavlicek

Solution: Hi Daphpavlicek. There’s no permanent fix for a hardware problem unless you have the device repaired or replaced. If this problem started after dropping the device before, there’s no software solution that can help. If you’re lucky and the issue is isolated to the battery or the charging port only, replacing them would fix the problem for good. In most cases though, unnecessary shock from accidentally dropping an electronic device results to permanent motherboard damage, which sadly, may not be fully repaired at all. Have the device checked by a professional so a thorough hardware check can be done.

Problem 4: Galaxy S7 edge can’t install Android Nougat in Cricket network

I currently have the Galaxy S7 edge plus on 6.0.1. Obviously 7.0 OS is out so I tried to check for software updates manually in the phone’s setting. When I go to check it asks “check at&t server for updates?”, so I  click yes and it tells me my software is up to date. To try and fix this I factory reset my phone but still nothing. Its stuck on 6.0.1. One possible reason, that I can think of, is that the phone belongs to AT&T and I bought it second hand from someone. I currently use Cricket wireless (which uses AT&T towers) and maybe for some reason because I do not have service with AT&T directly it does not properly check for software updates in their server.        — Ag.21

Solution: Hi Ag.21. Over-the-air (OTA) updates are Android updates provided by carriers to phones built for them. This means that these phones have modified Android versions developed by said carrier. AT&T phones run AT&T firmware only so if it you use it in another network like T-Mobile, you can’t expect to receive any OTA update. WE don’t know how Cricket Wireless network is set up but if your phone does not receive any firmware update, you can assume that Cricket is unable to provide updates to your AT&T phone at all.

If you want to install Android 7 on your phone, you’ll have to do it manually by flashing it. Flashing your phone is risky as it involves modifying core system files. If not done correctly, you may brick your phone. Also, you run the risk of losing features and services from Cricket that may be working right now. Make sure to work with your carrier before doing such a drastic solution.

Problem 5: Galaxy S7 stuck in Samsung logo screen after failed update

Good day. This is Eric, a guy from Ghana. I was actually using a customized Galaxy S7 which has trad or UAE and i used Odin to remove it. It was working fine as in 6.0 version and after that i had an update showing on my notification. so i updated and another update came up and it was 7.0. So i updated it to that but i couldn’t call anyone from my phone but i could receive calls. Then i later came back to use Odin with the old file and since then my Samsung has been showing only Samsung logo but can’t do anything about it. Please kindly help me because the was my last money i used to buy my phone. Thank you i hope to hear from you. — Sticky454545

Solution: Hi Sticky454545. Make sure that you flash the right firmware for your device. We can’t emphasize that enough. Using a wrong firmware version can lead to boot loop or other software problems. Remember, there are hundreds, if not thousands of Galaxy S7 firmware versions around the world. If, for example, you use a firmware version for an African country in your Asian device, you can’t expect your S7 to work.

This is one of the reasons why Samsung never encourage end users to tamper with the software. We know it’s within your right to do whatever you want with your device but if ever you’ll encounter problems like this, don’t expect Samsung or even third party support teams like us to provide you with a ready-made solution. When it comes to rooting- or flashing-related problems you must figure out the solution by yourself. There’s no way for anyone, even for Samsung, to know where the bug lies. There are hundreds of thousands of possible points of failure in an Android environment so it’s basically impossible to pinpoint the problem like the one you have.

The most that we can do to help is to tell you to reflash the device with its stock  or official firmware and hope for the best.  Other than that, you may end up with an expensive paperweight.

If you got the custom firmware from forum or website that entertains questions, try to reach out to them to see if someone from their community experienced this particular problem with this specific firmware. This is usually how other Android users who modified official software get issues resolved.

In some cases, flashing the bootloader to stock also helps. Try to see if reverting your phone’s bootloader can fix the problem before flashing the firmware itself.

Problem 6: Galaxy S7 won’t connect to mobile network

Hello! I have a Samsung Galaxy S7 and it is not connecting to the mobile network . I’ve selected the Network mode to Lte/wcdma/gsm, and at the network operators selected orange, restarted. Then i’ve tried to select automatically and still it haven’t worked. It gives me unable to connect

Also, I’ve taken out the SIM card and tried another and nothing works. I’ve also tried to update the software and because of this issue it doesn’t let me . Now I’ve returned the phone to the factory reset and still nothing. Please help me! Waiting for your answer. Thank you! — Ancaacroitoru

Solution: Hi Ancaacroitoru. We don’t know anything what you did before to cause this problem. If you’ve already checked if the phone’s APN settings are correct, we suggest that you contact your carrier for additional assistance. There may be other settings that must be enabled on their end, or in your device to allow it to work again in their network.

Problem 7: Galaxy S7 does not make sound notifications for SMS

My Galaxy S7 notifications all work except for my message notifications. I hear the notifications for my emails and Google calendar but not for any text messages. Recently in the past this was not an issue. Nothing with my phone has changed since then except for the update. I have turned up the volume on my notifications. I set my message notifications to sound when I receive a message. In my message settings, I made it so that my phone does not automatically delete old messages when they reach 1000. I read somewhere that if you have it set to delete old messages on the galaxy’s that It can make your message tones stop working. I changed my message notifications sound to a different one in my Zedge Ringtone App. I then also change my message notifications sound using the options that came on my phone rather then an app. Throughout all of this I did several soft resets. After nothing worked I turned my phone on in safe mode to check if a third party app installed on my phone is causing the problem. In safe mode incoming messages still did not give a sound. I did a factory reset about 6 months BEFORE the issue. Is there anything else I can try before going through the hassle of another factory reset? — Alexis

Solution: Hi Alexis. Try to wipe the cache partition first and see how the phone works. Here’s how:

  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. Using the Volume Down key, navigate through the options and highlight ‘wipe cache partition.’
  6. Once highlighted, you may press the Power key to select it.
  7. Now highlight the option ‘Yes’ using the Volume Down key and press the Power button to select it.
  8. Wait until your phone is finished doing the Master Reset. Once completed, highlight ‘Reboot system now’ and press the Power key.
  9. The phone will now reboot longer than usual.

If the problem stays afterwards, you can also try to wipe the messaging app’s cache and data before finally doing a factory reset.

To wipe an app’s cache and data, you need to do the following:

  1. Open the Settings menu either through your notification shade (drop-down) or through the Settings app in your app drawer.
  2. Navigate down to “Apps”. This may be renamed to something like Applications or Application Manager in OEM skinned versions of Android 6 or 7.
  3. Once in there, click on an application.
  4. You’ll now see a list of stuff that gives you information about the app, including Storage, Permissions, Memory Use, and more. These are all clickable items. You’ll want to click on Storage.
  5. You should now clearly see the Clear Cache and Clear Data buttons for the application.

Problem 8: Galaxy S7 won’t boot up, only restarts to Download mode

Hello and thank you for having a way of contacting you. Yesterday my phone crashed and stayed on the start up screen for 3 hours with no movement. The screen went blank (assuming it ran out of battery) and i put it on charge to see if i could fix the issue. When put on charge the charge logo came on but no green charging simulation on the battery logo. Red charging light also not coming on. I left it on charge overnight and no progress in the morning. When tried to turn on it either does nothing or crashes onto the Galaxy S7 start up screen. tried a soft restart, nothing. Tried a reboot and nothing. Tried another thing  called a custom os where the screen goes a turquise colour and warns me about updating software. There are 2 options at this point — push Volume Down to cancel and restart phone, volume up to continue with customs os. tried both. cancel does nothing and continue takes me to a screen where it says downloading and not to turn on but it stays on that screen for hours. I don’t know what to do from here. Any advice is appreciated Thank you. — Amy

Solution: Hi Amy. Since your phone appears to still boot to Download or Odin mode, you can try to flash the bootloader first. As mentioned above, flashing can potentially ruin your system so be sure to do research on how to do it properly. Below are the sample steps on how to flash a typical bootloader. Keep in mind though that the exact steps for your phone model may be slightly different. The following steps are only for demonstration purposes:

  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.

Flashing the bootloader is not a guaranteed fix so if it won’t work, you can try proceed to flashing a stock firmware.

Problem 9: Galaxy S7 won’t turn on, won’t boot to Recovery mode

Hi. I have a Samsung Galaxy S7 Edge. I was due the latest system update but kept postponing it and it was fine. it just stayed in my notification tray. I woke up in the morning and my phone would charge and showed the charging logo but wouldn’t turn on. I tried to boot in safe and recovery mode and no luck. Then I tried all the options in your boot loop page. http://thedroidguy.com/2015/06/how-to-get-samsung-galaxy-s6-edge-out-of-boot-loop-107653#BootLoopProblem1.  I have tried everything apart from flashing the firmware which I am not confident on performing. I have never installed custom roms or anything. I literally just postponed and update and woke up and now I am stuck in the “no command” loop despite trying everything including even a master reset. Any help would be appreciated. Kind Regards. — Danny

Solution: Hi Danny. Your phone won’t boot to Recovery mode so you really don’t have much choice except to try flashing. Unless of course you simply want to skip it by getting a new phone replacement.

 


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  1. I got the issue after flashing a kernel file….but I dont get it…the same kernel file I’d flashed earlier on and it worked…so how come it broke my system in this instance

  2. My galaxy J7(2015) only boots in download mode…no other mode works….I only get a single vibration when I try to get into recovery mode or try to boot up…followed by a black screen….not even a Samsung logo…completely black. There is no battery charging icon when I connect to power while the phone is off. I’ve tried flashing the latest official firmware several times but the issue persists. Anyone know how I can solve the issue or what exactly is going on?

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