How to fix Galaxy S8 no signal issue: cellular service disappears after an update

Hello and welcome to this day’s troubleshooting article. Today’s post will again address common problems encountered by some #GalaxyS8 users. Of particular importance that we would like to note here is on how to fix Galaxy S8 no signal issue. We know that there can be many variations to this issue so today’s main concern will focus more on what you can do if signal appears to be intermittent or disappearing randomly. We also bring 3 other issues so we hope you’ll find the post helpful.

Problem #1: How to fix Galaxy S8 no signal issue: cellular service disappears after an update

Last weekend my phone did a system update. I don’t know if the issues I’m having are related to that or not. But since then, I have gone from LTE to 3G. Then it started losing all internet connection. I don’t use wifi because I don’t have internet in my house. Eventually it started losing all signal entirely so I couldn’t even make any calls. It’s still doing all that intermittently. I have a Samsung galaxy S8. So the battery doesn’t come out. I’ve done: reset network settings, update profile, hard reset, restarting, and a full factory reset. Nothing has changed. I have sprint service and they tried to help me and nothing worked.

Solution: There are many variables to consider when dealing with this type of problem. Because a factory reset did not help anything at all, the remaining possible causes can include the following:

bad third party app
modem firmware issue
unknown software or hardware issue

Observe in safe mode

The first thing that you want to do right now is to check whether or not you have an app added causing the problem. There’s a fair chance that this might be the case since the issue persists even after a factory reset. If you simply reinstalled all apps after a factory reset without checking for the possibility that one of them might be the cause, now is the time to do that.

While on safe mode, only preinstalled apps will be allowed to run. So, if cellular service works, a third party app is to blame. These are the steps to boot your phone to Safe Mode:

Turn the device off.
Press and hold the Power key past the model name screen.
When “SAMSUNG” appears on the screen, release the Power key.
Immediately after releasing the Power key, press and hold the Volume down key.
Continue to hold the Volume down key until the device finishes restarting.
Safe mode will display in the bottom left corner of the screen.
Release the Volume down key when you see Safe Mode.
Observe the phone and check for the problem.

Safe Mode is a separate software environment. It’s a useful utility to check for possible third party app interference but it won’t pinpoint the exact one. If the problem does not happen on safe mode, which means a bad app is causing it, you then need to use the process of elimination to identify the culprit. Here’s what you need to do exactly:

Boot to safe mode.
Check for the problem.
Once you’ve confirmed that a third party app is to blame, you can start uninstalling apps individually. We suggest that you begin with the most recent ones you added.
After you uninstall an app, restart the phone to normal mode and check for the problem.
If your S8 is still problematic, repeat steps 1-4.

Continue working with your network operator

If the problem won’t go away even when your S8 is on Safe Mode, one of the two remaining causes must be to blame (modem firmware issue or unknown software or hardware issue. Because there’s no way to check which of them is the problem, you need to work with your carrier’s technical support team. Unlike us, they have access to your account and has firsthand knowledge about possible on-going network problems or issues with their own firmware. If the first level of support can’t help, then go up the ladder and talk to whoever is in charge who may have knowledge about the situation. We don’t think this is a device issue but if your network operator can’t explain why your device has no cellular service, then they should do more in terms of repairing or replacing it. We assume of course that your S8 came from your carrier. If it’s not, then you might as well try flashing older stock firmware (the version that worked fine before the upgrade).

Problem #2: What to do if your Galaxy S8 is totally dead and won’t turn on

I have a Samsung S8 that just went out of warranty 17 days ago. That sucks. But I have the black screen of death. There are no lights or indicators or sounds that come from the phone. But when I plug the phone into my laptop my laptop acknowledges that a new device has been connected and makes a noise and shows that the software on the device did not load properly. When I try to use the power and volume down button simultaneously after being held for 15 seconds the laptop makes a noise as if there’s an error message on the phone or the phone is trying to turn on or turn off. But there are no lights and no indicators on the phone whatsoever.

Solution: The noise that the laptop makes is probably just an indication that the phone’s battery may be trying to supply power to the system. The laptop’s USB connector may be getting power from the phone but that’s basically it. The phone is most likely dead due to component or motherboard failure. Where the specific problem lies is already beyond our ability to know. In this situation, a technician must physically check the phone and run hardware diagnostics to identify the problem.

In case you haven’t tried some basics yet, these are some of the troubleshooting steps that you can do:

use another set of charging cable and adapter
check the charging port for obvious damage or dirt
wait until the battery dies and charge again

If your S8 remains dead and won’t charge at all, you must be one of the unlucky users to have owned a smartphone. If upgrading or replacement is not an option for you, then we say let Samsung repair the device. That way, you can have a guarantee that your device will be handled properly by a trained professional.

Problem #3: What to do if Galaxy S8 keeps showing incomplete connection error

Same problem as one of your other users. An incomplete connection message about 8 out of 10 times I try and use the phone. Initially I waggled the charger and it would work period. finally the charger cable broke. I got a new one but the same message kept coming up old, bit less frequently. About 2 weeks ago it started coming up again more frequently. I tried it with a charger Cable in the car and went into Verizon who opened a new charger cable and the same thing happened. The phone is 6 months old. I called Verizon and after much passing back and forth between Verizon and the insurance company I finally called Samsung. So people know, while the phone is under warranty, you will have to send it back to them if you are nowhere near one of their repair centers. This means you have to persuade your carrier to give you a spare phone. After three hours I managed to persuade Verizon to give me a replacement phone. The replacement phone arrived and I have the same problems with the incomplete charger message. I’m very frustrated! And I just ordered a wireless charger.

Solution: Reports about “Incomplete connection” error on the S8 has been going on for months now but so far, Samsung is yet to respond to our queries. They may still be gathering information about this problem so at this time, we are left with troubleshooting it on our own. The thing is, there’s no known effective solution that figure out yet. We know that there are many users who reported the problem across the web and some of them did find out that it’s being caused by a bad cable issue. This is apparently not true in your case because you’ve already get a replacement cable so we’re looking at a possible software coding glitch. We would like to think that this is your case now since you’ve received a replacement phone with the same exact error. Frankly, we have no exact way of knowing if some S8 models or firmware versions are affected. The best thing that you can do though is to demand for another replacement device. And just to be sure, try to get a new Samsung Galaxy S8 charging cable and see if that will work with the new phone. We know this is a pain but it’s the only way for you to narrow down the causes.

Because there’s apparently a lot of S8 users still complaining about incomplete connection error, we will also monitor this trouble and update our posts about it if necessary.

For those of you who had not tried troubleshooting the issue yet, we suggest that you read this troubleshooting article.

Problem #4: Refurbished Galaxy S8 Plus has no signal

I just bought a refurbished Galaxy S8+ on Amazon for T-Mobile and I put my SIM in only to not get any network connection. I connected it to the hotspot of my tablet in hopes to update everything and it work. It did not. I came here for your article about resetting, checking the IMEI, etc. Did all but the firmware and still nothing. I went to T-Mobile, got a new SIM, let the employee see what she could do, and she said it could be defective. So I’m at a fork in the road. I already contacted the seller who is the insurance company of T-Mobile, so waiting on a reply.

Solution: For a smartphone to have cellular connection, there are a few basic things that must be met. The following are the required items:

phone hardware must be compatible with the network’s frequency or bands
if from a third party carrier, phone must be network unlocked
SIM card must be active
account must be properly provisioned
software must be compatible with network
if rooted or running custom ROM, there must be no mechanism that can block cellular services

All of these are basics. Make sure that all of them are checked by your carrier’s technical support team. Store representatives are usually not trained to handle technical issues (some of them may be) so try calling T-Mobile’s hotline instead and demand to talk to their technical support agent instead of their sales or customer service.