[HOW TO] Fix LTE Issue with CM 12.1 based ROMs and Sprint as your carrier

Nahaff

Member
Mar 8, 2014
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This may fix jfltespr on the Sprint network always worked fine with LTE on most ROMs, but not with very many ROMs lately.

It seems that the APN had one slight difference between ROMs that worked with LTE for me (older CM, stock TW, GPE), and ROMs that had no LTE or eventually dropped LTE (CM12.1 based). The bearer was not set to LTE in the APN profile for the ROMs that do not work for me. Changing that quickly fixed the problem (figuring it out took me much longer). I looked around a bunch when I had this issue, and found people with the same issue, but no solutions. So, that's why I post this here now. Here's the How To if needed:

Go to Settings, Mobile Networks, Access Point Names, and Sprint LTE internet.
Scroll down to Bearer and see what it is set to. Mine was Unspecified, and that's what was causing the issue. Set Bearer to LTE
Go back to APNs, and also set Bearer to LTE on Sprint EHRPD internet. I know that's not the normally selected APN, but if you only change Sprint LTE Internet, it seems to automatically change to this EHRPD one, and it still doesn't work.
That's it for now. Enjoy your LTE again on 5.1.1. It seems to be much smoother.
 

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qstarin

Senior Member
Feb 13, 2011
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I'm on an LG G3 but this APN/LTE issue seems to be affecting a lot of people on Android 5.1.x. I've been searching for solutions for days. Unfortunately, I have to report that your method did not work for me. With the Bearers changed to LTE I'm not getting any connection at all, but with them Unspecified I'll get a connection for a small time (<1min) after switching preferred network from 3G back to LTE before it drops again and gives me the exclamation point. If I leave it on 3G I have no problems retaining a 3G data connection. Nexus owners appear to be having this issue en masse with their 5.1.0 & 5.1.1 updates from google so it doesn't appear to be a CM issue, though CM had some APN related commits on July 1 that also seemed to cause problems for people and were undone by devs of some CM-based roms.
 
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Nahaff

Member
Mar 8, 2014
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Yea that's a bummer. Thanks for sharing though. Maybe having it happen to so many people means that it will get fixed sooner than later, but I can only hope. I can only speak for the Sprint version of the S4 running on the Sprint network. It seems that people with this exact phone are okay on other networks.

This fix wasn't 100% for me either. Every once in-a-while, I think mostly in particular locations, it'll get stuck on the exclamation mark, and I'll just have to throw it into airplane mode for a moment.

If you haven't tried yet, make sure to put the bearers to LTE for all APNs that have the same DNS name as the normal one that you use, and the others at their defaults. It's probably not the case, but your results sound similar to mine when I only set one of the APN bearers to LTE. I thought that might be worth a mention, but I'm sure there are deeper problems. Sounds like you probably already did that anyway...
 
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Irule305

Member
Oct 20, 2011
18
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I've been having problems with this too and I tried your method but it didn't help me. It's really frustrating when there's so many great roms that are useless but thanks for trying though. Hopefully it gets resolved soon.
 

manardj1

Senior Member
Jan 8, 2010
197
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AOSP automatically selects the correct APN as long as the bearer is unspecified. You can hard code the bearer, but then that APN is only valid for that bearer. In other words, setting the eHRPD bearer to LTE will make that APN only valid for situations where the radio is connected to LTE. However, the connection will fail because the APN settings are wrong and the system will automatically move to the next APN with the bearer set to LTE. This time the connection will succeed because the next APN is the LTE APN. If you set the eHRPD bearer to LTE then you will never get a 3g connection.

What exactly are the symptoms you guys are seeing with LTE? My wife and I are both running CM with no connection problems whatsoever.
 
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Irule305

Member
Oct 20, 2011
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AOSP automatically selects the correct APN as long as the bearer is unspecified. You can hard code the bearer, but then that APN is only valid for that bearer. In other words, setting the eHRPD bearer to LTE will make that APN only valid for situations where the radio is connected to LTE. However, the connection will fail because the APN settings are wrong and the system will automatically move to the next APN with the bearer set to LTE. This time the connection will succeed because the next APN is the LTE APN. If you set the eHRPD bearer to LTE then you will never get a 3g connection.

What exactly are the symptoms you guys are seeing with LTE? My wife and I are both running CM with no connection problems whatsoever.
For me, I just randomly lose data connection, both 3G and LTE. It will then reconnect a few minutes later. I tried removing the other APN like the freedompop & ting leaving only sprint APNs thinking that might help but it I still lose data.
 

manardj1

Senior Member
Jan 8, 2010
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For me, I just randomly lose data connection, both 3G and LTE. It will then reconnect a few minutes later. I tried removing the other APN like the freedompop & ting leaving only sprint APNs thinking that might help but it I still lose data.
Do you get an explanation point?

Take a modem log right after you lose data and send it to me in a PM.
 

beezerhale

Senior Member
Apr 8, 2013
97
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MMS ???

Hi. I am running CM12.1 and have tried other Lollipop roms. I am using Ting as my provider. I have two issues.

1. I don't get voicemail notifications. I can live with that.
2. Picture messages don't show. Texts come and go with no problem, just not picture (mms) texts.

Would these fixes help my issue? I have had no issues with 3g, which is most of my coverage area. I am usually on wifi anyway.

Thank you!
 

manardj1

Senior Member
Jan 8, 2010
197
109
0
Hi. I am running CM12.1 and have tried other Lollipop roms. I am using Ting as my provider. I have two issues.

1. I don't get voicemail notifications. I can live with that.
2. Picture messages don't show. Texts come and go with no problem, just not picture (mms) texts.

Would these fixes help my issue? I have had no issues with 3g, which is most of my coverage area. I am usually on wifi anyway.

Thank you!
Cm12.1 ignores the voicemail notification from the carrier. The MMS issue is an incorrect/missing APN. If you can figure out what it should be we can get a patch submitted.
 

manardj1

Senior Member
Jan 8, 2010
197
109
0
Hi. I am running CM12.1 and have tried other Lollipop roms. I am using Ting as my provider. I have two issues.

1. I don't get voicemail notifications. I can live with that.
2. Picture messages don't show. Texts come and go with no problem, just not picture (mms) texts.

Would these fixes help my issue? I have had no issues with 3g, which is most of my coverage area. I am usually on wifi anyway.

Thank you!
OK, it appears my data is not working, as well.

Is this what you need for a patch?

https://help.ting.com/hc/en-us/articles/205428698-GSM-Android-APN-Settings
Here is a jfltespr build that fixes Ting data/MMS. I strongly recommend a clean install. If that's not possible, be sure to reset APNs to defaults after you flash and then reboot. It will take a minute or two to get data after the reboot. Please let me know how it goes. If this does fix it, I will submit the patch. If not, I still have some ideas.

Be sure to make a nandroid backup as I couldn't get my wife's S4 to test it with and this was the first time I have built for the S4 on this machine.

https://www.androidfilehost.com/?fid=24052804347780285

This build is up to date with CM sources as of last night.
 

beezerhale

Senior Member
Apr 8, 2013
97
10
0
I am downloading now and will try it tonight. I appreciate the quick work. I am on Octo now, but really prefer CM. I will clean install. Thank you!


Here is a jfltespr build that fixes Ting data/MMS. I strongly recommend a clean install. If that's not possible, be sure to reset APNs to defaults after you flash and then reboot. It will take a minute or two to get data after the reboot. Please let me know how it goes. If this does fix it, I will submit the patch. If not, I still have some ideas.

Be sure to make a nandroid backup as I couldn't get my wife's S4 to test it with and this was the first time I have built for the S4 on this machine.

https://www.androidfilehost.com/?fid=24052804347780285

This build is up to date with CM sources as of last night.
 

beezerhale

Senior Member
Apr 8, 2013
97
10
0
Here is a jfltespr build that fixes Ting data/MMS. I strongly recommend a clean install. If that's not possible, be sure to reset APNs to defaults after you flash and then reboot. It will take a minute or two to get data after the reboot. Please let me know how it goes. If this does fix it, I will submit the patch. If not, I still have some ideas.

Be sure to make a nandroid backup as I couldn't get my wife's S4 to test it with and this was the first time I have built for the S4 on this machine.

https://www.androidfilehost.com/?fid=24052804347780285

This build is up to date with CM sources as of last night.
I loaded it on and everything works except for mms. My 3g is good, wifi, texts, internet, calls ... just no pictures in texts. Something I noticed was different from the other CM12 versions is that now I can see that the text was sent, I just can't download it. I tried these settings from this page - I used the EHRPD settings. They were able to make mms work using the Octo rom.

https://help.ting.com/hc/communitie...-not-triband-update-to-Lollipop-?locale=en-us
 

manardj1

Senior Member
Jan 8, 2010
197
109
0
I loaded it on and everything works except for mms. My 3g is good, wifi, texts, internet, calls ... just no pictures in texts. Something I noticed was different from the other CM12 versions is that now I can see that the text was sent, I just can't download it. I tried these settings from this page - I used the EHRPD settings. They were able to make mms work using the Octo rom.

https://help.ting.com/hc/communitie...-not-triband-update-to-Lollipop-?locale=en-us
MMS still doesn't work...no problem. I'll look at this link, make some more changes, and get back to you. A log might be helpful if you can.
 

bestiademon

New member
Jan 5, 2009
1
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AOSP automatically selects the correct APN as long as the bearer is unspecified. You can hard code the bearer, but then that APN is only valid for that bearer. In other words, setting the eHRPD bearer to LTE will make that APN only valid for situations where the radio is connected to LTE. However, the connection will fail because the APN settings are wrong and the system will automatically move to the next APN with the bearer set to LTE. This time the connection will succeed because the next APN is the LTE APN. If you set the eHRPD bearer to LTE then you will never get a 3g connection.

What exactly are the symptoms you guys are seeing with LTE? My wife and I are both running CM with no connection problems whatsoever.
I'm running cm12.1 nightlies with Freedompop as my carrier. This fixed my problem immediately.
 

manardj1

Senior Member
Jan 8, 2010
197
109
0
I'm running cm12.1 nightlies with Freedompop as my carrier. This fixed my problem immediately.
What fixed your problem? Setting the 3g bearer to LTE? That means the freedompop LTE APN is wrong and should be patched in the code. If we could get more input on this we could fix it for good.
 

copota

Senior Member
Jun 29, 2012
184
90
48
USA
I don't even have anything listed in my APN (I used to). How do I fix that?
Tap airplane mode, then tap again to turn airplane mode off. Then go into your APN menu. Your APN's should appear.

I'm running the latest CM 12.1 nightly. The stock APN's work for me, but I rarely get a LTE connection with them.

I've flashed the APN fix that's floating around, and it worked in older builds of CM 12, but recently the fix just disconnects and leaves me with no signal.

If I do what OP suggests, I'll get an LTE connection, but that leaves me with no 3G where LTE isn't strong.

I guess the problem with CM is that it cannot successfully switch between LTE and 3G correctly.

If you're not all that concerned about getting an LTE connection, I'd recommend just sticking with the stock APN's. Once you start flashing fixes, you're gonna have a problem.