Samsung Galaxy S4 -- text/phone/voicemail no-connect even with bars

Ok, here's a start

http://apn-settings.com/us/att-apn-settings/

4G seems to work out of the box, but still defaults to LTE. Haven't tried the 3G. Bleh, want 4G without LTE.

Perhaps these settings will circumvent the issue. Will post if I find more.

APN types

http://forum.xda-developers.com/showthread.php?t=1685273

default -- the default data connection. Can't co-exist with another

mms -- multimedia messaging services -- needed for texts

supl -- Secure User Plane Location -- location services

hipri -- High Priority mobile data

fota -- Firmware over the Air -- updates (this is the only one missing from the APN link before vs my default. Not sure if this may/may-not be the issue)

there's one called "dun" for wifi sharing? "admin" and "internet"

some sites recommend listing nothing, which may default to some of them. Sounds like a pile of instability to play too much with this.

AT&T has a site for devs themselves.

https://developer.att.com/technical-library/apns/apn-descriptions-and-characteristics

Lots of info here, playing with lots of settings, good luck, won't post again until I get a real response or find a formula that is stable and actually "communicates" with my wife without fail

Took some time to experiment APNs, for those that care. Doesn't solve the issue, but easily gets a 2X LTE speed uplift. Goes as fast as WIFI. Odd that such trite settings can affect so much:

Settings-->Connections-->More networks -->Mobile networks-->Access Point Names

Hit the '+' in the upper right

Name : ATT other  (name is not relevant)

APN : phone  (other choices are broadband, etc. You want 'phone')

MMSC: http://mmsc.mobile.att.net

Multimedia message proxy : proxy.mobile.att.net

Multimedia message port : 80

MCC : 310

MNC : 410

APN type: default,supl,mms,internet

Bearer: LTE  (only if you're around towers with LTE, otherwise leave unspecified)

leave the rest blank/default

"hipri, fota, admin" have measureable disadvantages (ping, download/upload)

"internet" and bearer : LTE have measurable advantages

Again, neither solves the actual problem of random drop. Still have two cases open about the issue, but another two weeks, I'm dropping the network.

If anyone else has feedback, do tell, I'm kind of out of ideas besides rooting.

Thank you for posting all of this!  My wife and I have been going crazy with this exact problem.   We got our S4s in March, and they worked just fine until about a month ago.

We have been to 3 different AT&T stores, and the people we dealt with had no clue and acted like they had never heard of this problem.  At one of these these stores the the rep removed the battery and then plugged it back in.  At the next one, the rep gave us new sim cards.  The problem came back after each of these "fixes."  At the last AT&T store, the rep suggested that since the phones are still under warranty, we should return them and have them replaced.  I assume this replacement would be a refurbished phone which for all I know would have the same problem.  We have also gone three times to see the Samsung rep at our local Best Buy.  On the first visit, she changed our APN settings, I believe to the exact settings you have spelled out.  I don't have the phone with me at the moment, so I can't confirm that. The same malfunction was back again the next day. The next Samsung rep reflashed our software, and the problem was back after 2 days.  We went back again and saw the same rep who had changed our APN settings, and she told us all she could suggest is to go to the Samsung authorized repair center in a nearby city.  We did, and the rep there told us their protocol was to reflash the software and then if that failed, to change out the motherboard.  For this last step, they have to get approval from Samsung. We talked them out of doing the reflash since it was done a few days ago and didn't work.  So at this moment we are waiting for the approval.

I'd consider dumping AT&T, but when I research this problem on the internet, I am seeing people on Sprint and Verizon who have the same problem.  The consensus I'm reading among these people is that the KitKat 4.4.2 "upgrade" is not getting along on a friendly basis with a great many (but not all) S4 phones.  I am emphatically not technical-minded, so I can't give an opinion on that.

We are among the last people on Earth to get a smart phone (these are our first), and we have been wanting our old flip phones back.  In fact, I am pushing to revert to the old Western Electric rotary-dial that we still have in the closet.

I'm here in Austin with an S4 and have the same issue.  Been updating AT&T Mark the Spot and talked to AT&T reps on phone and in the stores and thus far, none have been any help.  Hoping someone can find a solution to this.

Thanks for the responses guys, glad I'm not going nuts as the only one seeing this. I just found some other threads experiencing the same thing.

Anyway, found something super hacky. "Test mode"...looks like admin access to settings and network stats in your phone.

In your phone dialer

*#*#4636#*#*

Then look in Device info. Try changing LTE/GSM auto (PRL) to GSM auto (PRL). This forces HSPA (4G) only mode without the LTE, which is my guess what's wrong. Your download speeds will go from 6Mbps to like 2Mbps, which sucks, but whatever, WiFi + working phone/texts is better than brokenness.

I think these settings go back to default if you reset.

My guess is 4.4.3 will fix all this mess. Anyway, try it out, let me know if you have success with this.

Hello, been experiencing same tech difficulties and am currently waiting on a replacement. Apparently the warranty phone will not fix this. What I am wondering is this problem limited to only s4 or is it showing up in s5 as well? My phone worked well til I got the update with the Isis wallet and other b/s from att. Thanks att. Is there any way to revert to the prior o/s without ruining the warranty? I will keep calling them for warranty phones until they fix this.

its a samsung problem on all carriers but only effects like 4% of the phones out there.   And I've read post with the s5 doing the samething

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@MoarDots wrote:

In your phone dialer

*#*#4636#*#*

 

Then look in Device info. Try changing LTE/GSM auto (PRL) to GSM auto (PRL). This forces HSPA (4G) only mode without the LTE, which is my guess what's wrong. Your download speeds will go from 6Mbps to like 2Mbps, which sucks, but whatever, WiFi + working phone/texts is better than brokenness.

 

I think these settings go back to default if you reset.

 

My guess is 4.4.3 will fix all this mess. Anyway, try it out, let me know if you have success with this.

 

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Can confirm with my phone and wife's phone, this does indeed work. Sprint/Verison had the same problem Spring 2013 when they migrated OS's and did something to LTE (tis where the solution came from). They seemed to figure it out in 2 months. ATT is having the issue now, T-Mobile never had it. Yes, S4s and S5s.

Drop to 4G without LTE for the time being and wait for 4.4.3 to fix it. Or jump if that's insufficient. There's enough noise in ATT about this now, so if they ignore it, shame on them.

Happy hacking!