How to fix Galaxy S8 network issue: switches from 4G to 3G or won’t send or receive texts

Hello everyone! Like in other troubleshooting articles, today’s post will answer some cases that we gather from your letters a few days ago. We plan on adding more #GalaxyS8 troubleshooting posts in the coming days so if you contacted us recently about your own issue, be sure to check other articles in the next few days.

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: How to fix a Galaxy S8 that’s stuck in boot loop after flashing

I tried to downgrade my s8 software version via odin. however when I did it it booted up fine and installed everything fine. as soon as it booted it told me something about the validation couldn’t be verified and asked me to reset, I wasn’t able to do anything else with it, I pressed reset and it has put me in a constant “samsung logo -> erasing with android logo and a spinning wheel -> reboot” loop and won’t even let me access recovery mode no matter what, I can only launch in odin mode. Could you please provide assistance as I’m completely out of ideas… Kind regards.

Solution: First of all, we want to make it clear that we assume you’re aware of the risks involved when tampering with official software. Since only seasoned Android users attempt to flash their devices, you should be ready to accept the fact that you may have seriously messed up your device and there may be no way to fix it.

Secondly, boot loop issue often occurs after flashing because of a lot of factors. Some of the common causes include the following:

using incorrect firmware
unknown PC glitch
phone software bug
defective USB cable or port (either in PC or phone)
not following correct flashing instructions (for a particular firmware build)
presence of bootloader bug

Any of these items may have caused the problem. Knowing which one is impossible though. There’s no way if your phone can still be fixed. The answer depends on the cause.

Thirdly, the only possible solution is to flash stock firmware to your device. We assume you listed important software information of your device before you flashed it. Based on that list, try to find the same exact firmware version and flash it to your S8. Under normal circumstances, you should be able to fix boot loop issue. If you don’t know the stock firmware of your device, try to do some online research or ask users of the same model from the same carrier.

If flashing stock firmware won’t work at all, you’re out of luck. If the phone is still within warranty, bring it to Samsung Service Center. Don’t mention that you tried to tamper with the software. If you’re lucky, Samsung may help you fix the device or replace it.

Problem #2: How to fix Galaxy S8 network issue: switches from 4G to 3G or won’t send or receive texts

I am having data connection issues. My phone will switch from 4G to 3G even in a good signal area. I can turn airplane mode on and off to get 4G back. Sometimes it wont send messages or receive them either. Says i have no data connection even when it shows i have 4G when i try to send a text. I can turn airplane mode on then off or make a phone call then I can send them. I can be using other apps such as clash of clans or Facebook messenger and still have to cut my signal on/off with airplane mode or phone call to receive and send messages. I believe my problems are caused by the same issue. Do note that this a refurbished Verizon Samsung Galaxy S8 switched to Straight Talk service. And the issues still occur when I have a brand new unlimited service plan added with full data. It’s the $55.00 plan from Straight Talk. I have seen a factory reset fixed a lot of S8 problems. I am trying to avoid that. If I have to i will. Will a factory reset mess with the service plan I currently have? My service plan doesn’t expire for almost 2 weeks.

Solution: While it’s good that carriers nowadays make it easier for their customers to switch to other networks by offering factory unlocked devices (or network unlocking them), it doesn’t fully eliminate the fact that there may be bugs or limitations following the switch. This is due to the fact that each carrier has their own Android firmware version. Even when a phone has been network unlocked, its software or hardware may not be fully compatible with the system of the second network.

If your problem has been there since day after you switched to Straight Talk, you can assume that the bug may be caused by a firmware restriction or incompatibility. Whether that’s accurate is up for debate but unfortunately, there’s really no way to tell. It can take a lot of resources, right people, specialized tools and a long time to figure out the bug. In other words, knowing the cause is very impractical and totally uneconomical. We don’t think there’s someone or group that will devote their effort and resources to know the real cause.

If you want to figure out yourself, there’s a limited set of troubleshooting steps that you can try. They don’t involve deep coding checks though so you may not be able to really know where the problem lies if the basic steps won’t help. Below are the things that you can try.

Wipe the cache partition

A lot of bugs can occur if your phone’s system cache is corrupted or out of date. Be sure to refresh it by wiping the cache partition. Here’s how:

Turn off the device.
Press and hold the Volume Up key and the Bixby key, then press and hold the Power key.
When the green Android logo displays, release all keys (‘Installing system update’ will show for about 30 – 60 seconds before showing the Android system recovery menu options).
Press the Volume down key several times to highlight ‘wipe cache partition’.
Press Power button to select.
Press the Volume down key until ‘yes’ is highlighted and press the Power button.
When the wipe cache partition is complete, “Reboot system now” is highlighted.
Press the Power key to restart the device.

Reset network settings

Some network bugs are due to incorrect network settings. Try to refresh your device’s network configuration and see what happens.

From the Home screen, swipe up on an empty spot to open the Apps tray.
Tap General Management > Reset settings.
Tap Reset Network settings.
If you have set up a PIN, enter it.
Tap Reset settings. Once complete a confirmation window will appear.

Use another SIM card

Some users fix texting or calling issues by simply disconnecting the SIM card. If you haven’t tried it yet, be sure to do so. After removing the card from the device, wait for about 10 seconds before re-inserting it.

Install updates (if available)

This one depends if your device can still receive updates or not. Normally, unlocked phones used in a second network won’t get over-the-air updates. If your phone continues to receive updates from Samsung, be sure to install them. Some network bugs are fixed by updates only so don’t skip them.

Factory reset

Factory reset is not usually recommended for unlocked phones because it returns everything to their defaults. Since unlock codes are artificial software modifications, they can be deleted if you do a factory reset. This means that your phone may be locked to its original network again after a reset. If you think you can get the phone network unlocked again after a reset, be sure to try this solution.

To factory reset your S8:

Back up data on the internal memory. If you have signed into a Google account on the device, you have activated Anti-theft and will need your Google credentials to finish the Master reset.
From the Home screen, swipe up on an empty spot to open the Apps tray.
Tap Settings > Cloud and accounts.
Tap Backup and restore.
If desired, tap Back up my data to move the slider to ON or OFF.
If desired, tap Restore to move the slider to ON or OFF.
Tap the back button to the Settings menu and tap General Management > Reset > Factory data reset.
Tap Reset device.
If you have screen lock turned on, enter your credentials.
Tap Continue.
Tap Delete all.

Should the issue remain after a factory reset, you can assume that the problem is not fixable on your level. This may be one of the idiosyncrasies of your device being used in a particular network, or there may be an inefficient firmware coding behind it.

Problem #3: Galaxy S8 freezes and shows error when opening an app

I have had this phone for about a few months now and just today this problem came up. I had gone to look at some news on the KSL app and the next thing I knew I see the error. This is the first time it has happened since I had the device and I have no clue what app is causing it or why. I cannot get the device to power on, as it is either stuck or frozen on that error screen. I have not attempted to root or modify my device in any way, shape, or form. I would be grateful to receive professional help and assistance to get rid of the issue.

Solution: If you are not able to power on the device, how do you know that you are getting an error? Do you mean to say that your phone becomes unresponsive or freezing when an app error comes up? If that’s the case, we recommend that you erase the app from the device. Here’s how to do that:

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.
Now that the phone is on safe mode, go to the Home screen and find the app. Tap and hold the said app, then select uninstall to remove it from the system.

Alternatively, you can uninstall the app with these steps:

Boot to safe mode.
Open Settings app.
Tap Apps.
Find the app you are having an issue with.
Tap Uninstall button.