Rooted Galaxy S6 keeps crashing and showing signs of slow performance, other S6 issues

S6 Knox

Welcome to another post that addresses some of the #GalaxyS6 problems shared by some members of our community. These are the specific topics covered in this article today:

  1. Galaxy S6 battery won’t charge beyond 0%
  2. Cannot turn off Ultra Power Saving Mode on Galaxy S6
  3. Galaxy S6 not recognizing any SIM card and won’t connect to network
  4. How to retrieve photos from a Galaxy S6 Edge Plus that won’t turn on
  5. Galaxy S6 stuck in “Downloading…Do not turn off target” screen
  6. Rooted Galaxy S6 keeps crashing and showing signs of slow performance

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, or you can install our free app from Google Play Store.

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 S6 battery won’t charge beyond 0%

My phone initially would not turn on. It also would not charge. When I connect the original fast charger that came with the phone, it would show a dead battery symbol, then switch to a symbol showing 0% charge saying charging, but then would have a green flashing LED light right above the home button. After leaving the phone plugged in for over an hour, it still read 0% charge and would not start. 

I have tried using a soft reset with no luck. I have not tried a hard reset yet. When the phone wasn’t working, I activated an old phone so I would have phone service. If I need to do a hard reset, I will re-activate this phone so I can use Verizon’s backup and then try the hard reset.

I have also tried booting in safe mode, phone was able to boot, but still would not charge.

I was able to boot phone using the volume down, power, home button combo. Still will not go above 0% charge.

I have had the phone since September of last year, so unfortunately, it is no longer under warranty.

Can you help?

Thank you. — Roy

Solution: Hi Roy. Looks like the only remaining potential solution for you is doing a factory reset. Attempting to restart the phone in safe mode and Odin mode are part of the software troubleshooting that can be done for this type of problem and apparently they’re of no help. Kindly do a master reset and see if it will make any difference. If that won’t work either, consider having the battery or the phone itself replaced.

For reference, here are the steps how to do a full reset of a Galaxy S6 series:

  • Turn off the device.
  • Press and hold the following three buttons at the same time: Volume Up key, Home key, and Power key.
  • When the phone vibrates, release the Power key but continue to press and hold the Volume Up key and the Home key.
  • When the Android System Recovery screen appears, release the Volume Up and Home keys.
  • Press the Volume down key several times key to highlight ‘wipe data / factory reset.’
  • Press Power button to select.
  • Press the Volume down key until ‘Yes — delete all user data’ is highlighted.
  • Press Power button to select and start the master reset.
  • When the master reset is complete, ‘Reboot system now’ is highlighted.
  • Press the Power key to restart the device.

Problem #2: Cannot turn off Ultra Power Saving Mode on Galaxy S6

The phone won’t let me off of Ultra Power Saving Mode. I didn’t see a topic on this (if there is for S6 please can you direct me) but I put ultra power saving on and when trying to disable it the screen simply says ‘disabling upsm’ and loading, when loading it doesn’t let me use any other apps and the only way I can access the 6 things on upms is if I restart or switch off my phone. I’ve left it to ‘disable’ upsm for an hour or more, have tried the soft methods of restarting, switching off and rebooting in safe mode but nothing has so far worked, I also want to avoid doing a complete factory reset since I have a lot of notes on the phone that I do not want to lose. thanks in advance! oh, my mobile provider is Vodafone which I think is Verizon in America. — Geena

Solution: Hi Geena. The only effective workaround for this problem that we know is to boot a Galaxy phone in safe mode then switching to another launcher other than TouchWiz. Once you’ve selected a different launcher, you should be able to go back to Ultra Power Saving Mode screen to disable it normally. We’ve tried this on a Galaxy S5 but we are not sure if it also works on a Galaxy S6. It appears that there’s a bug is generated when you use TouchWiz launcher while UPSM is on.

If this workaround won’t work on your unit, please do a factory reset.

Problem #3: Galaxy S6 not recognizing any SIM card and won’t connect to network

Phone was working fine. Almost of a sudden it won’t connect to my current network provider. I can’t make or receive calls or texts or connect to the mobile network. Have tried the SIM in friend’s phone and it works so the error is not the SIM card. Tried a friends SIM in my phone and hers will not work. So appears error with actual phone. Can connect to wi-fi no problem.

When I search networks and select my mobile network, I get an error message saying unable to connect. On home screen it says emergency calls only and cannot connect to mobile network or no service mobile network. Are there some settings that have changed in network settings that I need to check? — Lianne

Solution: Hi Lianne. That your friend’s SIM card does not work on your phone either seems to suggest that the device is not reading any SIM card at all. This may mean that the SIM card slot has been damaged, or a software glitch has messed up the operating system. We suggest that you try a factory reset first to see if that will change something. Should the issue remain, call Samsung or your wireless carrier so you can have the phone replaced.

Problem #4: How to retrieve photos from a Galaxy S6 Edge Plus that won’t turn on

I have recently brought a Samsung Galaxy Edge Plus. The battery has died and is not charging so there is no way to access the phone or turn it back on.

Although I have insurance on the phone, I have just got back from a weekend in Italy and all of my photos are on the phone (my phone decided to break when i was on holiday and stopped charging and as a result I have been unable to back up my pictures).

As I need to get my photos off the phone before I can send it off, is there anything I can do to get a temporary fix to either get the photos off the phone or to access the hard drive? — Sunam

Solution: Hi Sunam. First of all, try using another working charger to see if the issue has something to do with the charger or cable. Alternatively, you can also try to charge the phone wirelessly to see if that will power the phone back on.

Now, the only way to access your S6’s storage device is ensure that’s powered. The Nandroid chip that stores your data won’t work if power is turned off. If your phone won’t turn on, there’s just no way to retrieve those photos. Please call Samsung so they can diagnose the issue. The battery may have simply failed so if they can replace it, you should still be able to use your phone as if nothing happened to it.

If battery replacement won’t work either, then you’re simply out of luck and those photos will be never be recovered.

Problem #5: Galaxy S6 stuck in “Downloading…Do not turn off target” screen

Hi. Two nights ago the phone just stopped charging even when connected. The next morning I realized that it did charge a bit even though it did not show the charging symbol. Then it completely shut down. The screen went blank. For a little while it showed two lines on top left corner which mentioned about Boot failure (sorry but i don’t remember the exact message). This was then replaced by the “Downloading…Do not turn off target” message.

I have gone through your detailed instructions regarding this error and tried everything that you have mentioned there. However the phone just does not boot in any mode. Currently even after placing it on charge it shows neither the 2 line errors on top nor the “Downloading…Do not turn off target” message. The phone heats up mildly even with prolonged charging but is not very hot.

I don’t mind letting go of the phone and replacing it with a new one. But the issue is I have not backed up any of my data. Is there any hope of retrieving my data? Even if i get just my contact numbers that itself would be enough. Regards. — Tarang 

Solution: Hi Tarang. The “Downloading…Do not turn off target” screen means that the phone is stuck in Odin mode. Under normal circumstances, a user can simply restart the phone to boot back to normal mode and everything should be fine. If this is not happening, that’s an indication that the phone is unable to complete the boot sequence normally. This usually happens if the current operating system is corrupted, or if a flashing procedure has gone wrong. Your only way out of this mess is to either flash a stock firmware, or try to go to Recovery mode, delete the cache partition, and perform a factory reset. Any of these procedures — flashing a new ROM or doing a factory reset — means losing user data like photos, videos, contacts, etc.

If you don’t to do any of that yet, consider using ADB as a potential solution. Android Debug Bridge is PC utility that you can install on your computer so you can access the software on your mobile. If you want to know more about it, please use Google how to use it on your Galaxy S6.

Problem #6: Rooted Galaxy S6 keeps crashing and showing signs of slow performance

Since I got my mobile one year ago, it started running slower and crashing more.

Also, the internet went from two to one bar and even disconnects sometimes.

I haven’t made any recent changes to my device. It is rooted, but it has been so for the past half year and the problems only started occurring after a couple of months.

I clean out my cache recently, and try to use as less storage as possible. I haven’t installed many apps.

Do you have any idea why my phone might be slowing down? When my iPod did slow down, I formatted it using iTunes. However, I think that might not work with an Android device.

Is it necessary to reformat my device and reinstall my OS and if so, how should I do that?

Also, I’d like to have my phone rooted, which I did with Chain Fire auto root, but I’m worried it might be what’s causing the device to slow down. What would be the safest way to root my device?

Thank you very much. — Jair

Solution: Hi Jair. There are many reasons why an Android device crashes or appears to show signs of slow performance. The causes can range from bad hardware, apps, storage issues, or even connection problems. The thing is, there is no easy way to know what the true cause is. You must identify the problem yourself first and in your case, the best way to start is by checking if it’s software-related. Because a rooted device can install unofficial apps, or those that do not pass the quality checks required of apps available in Google Play Store, it’s possible that one of the installed apps is to blame.

The next troubleshooting step that you want to do then is to boot your phone in safe mode for as long as you want so you can observe how your phone behaves. While in safe mode, third party applications will be prevented from running. If the issue fails to occur while this mode is enabled, that’s an indication that one of them is the culprit. Here are the steps to boot your phone in safe mode:

  • Press and hold the Volume Down and Power keys for 20 to 30 seconds.
  • Once you see the Samsung logo, release the Power key immediately but continue pressing the Volume Down key.
  • Your phone should continue booting up and you will be prompted to unlock your phone as usual.
  • You will know if the phone successfully booted in safe mode if the text “Safe mode” is displayed at the lower-left corner of the screen.

We recommend that you keep your S6 in safe mode for at least 24 hours so you can see the difference in performance. Should nothing change though, your next step is to wipe the cache partition.

For minor firmware-related issues brought by apps and firmware updates, wiping the cache partition often does the trick. It’s because this procedure will literally delete all cached files in the cache partition, which will force the system to create new ones during the next boot up.

This procedure is also very helpful in fixing issues like slowness, crashes, random reboots, boot loop, stuck during boot up and random freezes after updates. Here’s how you wipe the cache partition on your S6:

  • Turn off the device.
  • Press and hold the following three buttons at the same time: Volume Up key, Home key, and Power key.
  • When the phone vibrates, release the Power key but continue to press and hold the Volume Up key and the Home key.
  • When the Android System Recovery screen appears, release the Volume Up and Home keys.
  • Press the Volume Down key to highlight ‘wipe cache partition.’
  • Press the Power key to select.
  • When the wipe cache partition is complete, ‘Reboot system now’ is highlighted.
  • Press the Power key to restart the device.

If you installed a custom Recovery on your phone like Clockworkmod Recovery and TWRP Recovery, the process of wiping the cache may be slightly different. Use Google to look for the steps how to wipe the cache partition for a certain custom Recovery. After wiping the cache, observe the phone for 24-72 hours and try to use as many apps as possible.

Now, if nothing changes, a more drastic software solution may be required. Doing a factory reset almost always fixes software problems so it’s a highly recommended final solution. If you don’t want to remove the root on your phone, make sure that you factory reset by going under phone Settings and not via recovery mode. After a factory reset, observe the phone again for another 24 hours without installing any apps.

If you want to see if the current root software is causing the problems, simply flash a stock firmware on your phone.

The answer to your question about the safest way to root your device actually depends on you. We’ve noticed that a lot of S6 users are using PingPong Root and ChainFire Auto Root but both of them are also known to cause issues here and there. The reported problems may not entirely be due to a bad root software but rather on other variables that can come into play in a system. Android users who decide to root their phones and install custom software should accept the risks involved. The safest fallback though is to simply flash back to stock firmware if unfixable problems start to show up. Keep in mind that developers of rooting and custom software are seldom paid for their hard work and so their product may be far from perfect. They operate on best effort mode so if you’ll encounter problems after using their software, try to contact them for direct assistance.


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