How to fix Sprint Galaxy Note 4 latency during calls with the screen going black [Post Lollipop]

This post will serve as an answer to the question sent to us by one of our readers whose Sprint Galaxy Note 4 is having issues while in a call. According to him, there’s latency and that the screen goes black. These issues started after he updated his phone to the most recent Android 5 Lollipop firmware.


While our reader tried to clearly explain his problems, we still have questions. For example, the word “latency” is vague and since it happens during a call, there’s always a chance it’s network related. However, since it started happening after an update, there’s also a good chance it’s a firmware-related issue.

If you have the same device and experiencing any of the issues our reader mentioned in his email, the troubleshooting procedure I used in this post may be helpful to you as well. Before anything else, though, here’s the actual email our reader sent:

“System is just freezing all the time and when I go to make a call there is latency as the screen goes black and then slowly transforms my caller information. Ever since this lollipop software has been installed I’ve had nothing but problematic issues. I am of sound mind and proper wit and I am NOT Green when it comes to technology so I also treat people with much respect and I really appreciate you helping me resolve these issues because being kind of a tech guy I have updated the firmware , prl, etc… please help!

I will forever be your best friend haha.!. However, I sincerely do appreciate your time and perhaps uncovering potential issues and then the proper guidance with which to reasonably resolve these issues if we can escalate it as well that would be wonderful I am a true hard working individual and being a record producer and engineer in the recording business I am very reliant on this device and I’m a huge fan of Samsung so I am very optimistic we can reach a situation of correction and once again, thank you so much for your prompt attention to this matter.” — Brian

Before we proceed to our troubleshooting, if you have other issues with your phone, visit our Galaxy Note 4 Troubleshooting page as we’ve already addressed a lot of problems before. You may try the solutions we provided and if they didn’t work for you, then fill up this form accurately and we will help you find solutions to your problems.


The procedure I will use in this post is based on how we will actually troubleshoot phones having problems like this. Please note that we are basing everything on how our reader described the problems. Needless to say, the accuracy of the procedures we use depends on how accurate the information fed to us because we couldn’t physically inspect the phone.

We don’t force you to follow what we tell you in our articles and while we are sometimes tempted to venture out with risky procedures, we prefer to remain in the safe zone because first, we don’t want to create more problems especially if we don’t know what the real issue is; second, we don’t want to void your warranty by making you follow unconventional troubleshooting procedures.

Latency during calls

By “latency” I would assume our reader meant there are times when he can’t hear the caller and vice versa. Or, it could also be that the voice becomes robotic, weak or there are static on the line. To isolate this problem, here’s what you’re going to do…

Step 1: Make outgoing calls and observe. Observe if the latency happens to every call. You may also try asking your friends to call you just to find out if it also happens to incoming calls. The purpose of this step is to know if it’s a network-related issue or it’s a problem with the newly-installed firmware. If it doesn’t happen to every call, take note of its frequency because if the latency occurs more often than not, it’s a firmware issue.

Step 2: Boot in safe mode and make calls. Assuming it’s a firmware issue (because there’s not much we can do for network-related issues) and it happens to every call. The next thing you should do is boot the phone in its barebones and try to make outgoing calls again. Boot it in safe mode to temporarily disable all third-party apps and load only the default services. You can still make and receive calls even in safe mode.

  1. Turn off the phone completely.
  2. Press and hold the Power key and the Volume Down key.
  3. When the phone starts to boot, release the Power key but continue holding the Vol Down key until the phone finished restarting.
  4. Safe mode will be displayed at the lower left corner; you may release the Volume Down key now.

If the same thing happens, then proceed to the next step.

Step 3: Boot in recovery mode and wipe the cache partition. Wiping the cache partition to delete all caches is safe to do. None of your data or files will be deleted; just the files used by the system to make apps and services run smoother. Considering it is a firmware-related problem, or at least, it started to happen after an update, then there’s a chance some of the caches got corrupted but still used by the new system. You need to delete them so that Android will be forced to create new files.

  1. Turn off the Galaxy Note 4 completely.
  2. Press and hold the Volume Up and the Home keys together, then press and hold the Power key.
  3. When the Note 4 vibrates, release both the Home and Power keys but continue holding the Volume Up key.
  4. When the Android System Recovery shows on the screen, release the Vol Up key.
  5. Using the Volume Down key, highlight the option ‘wipe cache partition’ and press the Power key to select it.
  6. When the wiping of the cache partition is finished, highlight ‘Reboot system now’ and hit the power key.

Once the phone has successfully booted up, try to make calls again and see if it did make a difference. If the problem remained, then you have no other option but to proceed to a more complicated procedure.

Step 4: Perform the master reset. If all else fails, there’s no other way to fix the problem but a master reset. It will delete all your data, settings and files stored in your phone’s internal storage so make sure you make a backup of every file you don’t want to lose. I understand it’s a hassle on your part but that’s one thing you have to undergo to know if the firmware needs to be re-flashed (re-installed manually).

The master reset is basically just a factory reset but instead of just deleting all data and files in the phone’s internal storage, it will reformat the data partition, which will delete all files that couldn’t be deleted by doing the latter. Here’s how…

  1. Turn off the Galaxy Note 4 completely.
  2. Press and hold the Volume Up and the Home keys together, then press and hold the Power key.
  3. When the Note 4 vibrates, release both the Home and Power keys but continue holding the Volume Up key.
  4. When the Android System Recovery shows on the screen, release the Vol Up key.
  5. Using the Volume Down key, highlight ‘wipe data / factory reset’ and press the Power key to select it.
  6. Now highlight ‘Yes — delete all user data’ using the Vol Down key and press the Power key to begin the reset.
  7. When the master reset is complete, highlight ‘Reboot system now’ and hit the Power key.
  8. The Note 4 will restart but it will be longer than usual. When it reaches the Home screen, then begin your setup.

Should the master reset fail to resolve this problem, then contact your provider and have its tech take a look at it. As I mentioned earlier, the firmware may need to be re-flashed.

Screen going black during calls

By default, all Galaxy devices have a feature that turns off the screen automatically during calls. One of the purposes is to prevent a call from being disconnected when the phone touches your face. If the screen turns black during calls when you put the phone near your face but automatically lights up after the call, then there’s no problem with your device. If you don’t like that then set the phone to keep the screen lit up during calls by going to Call Settings.

However, if the screen remains black after every call, then that’s the problem but not a serious one. It must be an issue with the sensor. Recalibrating it will fix the problem or if you already did the master reset, then you shouldn’t worry about it anymore.

Now, about the other issue, I really can’t understand how the caller information is “transformed” or what it transforms into. It can be a glitch in the service or app that handles contacts and if you already did the reset, it may have been fixed already.

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We are always open to your problems, questions and suggestions, so feel free to send them at [email protected] We support every Android device available and we are serious in what we do. This is a free service we offer and we won’t charge you a penny for it. But please note that we receive hundreds of emails every day and it’s impossible for us to respond to every single one of them. But rest assured we read every message we receive. For those whom we’ve helped, please spread the word by sharing our posts to your friends or by simply liking our Facebook and Google+ page or follow us on Twitter.

2 Replies to “How to fix Sprint Galaxy Note 4 latency during calls with the screen going black [Post Lollipop]”

  1. Your advice of clearing the cache fixed my problem. I would make a call by selecting the person to call, looking at the screen at normal viewing distance, I pressed the call button and imediately the screen went blank. The phone had not moved towards my face and the proximity sensor is neither dirty or blocked, so that wws not the issue. This happened at the first call I made after upgrading to the latest version in my Galaxy Note 4. The screen goes black as soon as it get to my ear and comes back on as soon as I takit away. So I agree with your assumption that there was something in the Cache causing it.
    Thank you for your advice.

  2. Mmm, I just learned something, it never occurred to me why the screen goes black when you make a call,
    thank you !

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