Develop Bugs

[Q] help!3G connectivity has gone from my phone

my phone can not connect to 3G networks in most of our city, while it used to work just fine in these same places. at first i thought there must be something wrong with the carrier's base stations. but today i tested my SIM card on another LU6200(Korean version of Nitro HD) and it works perfectly both on 3G and 2g networks on that phone. but when i put it back into my phone, it can only get 2G signal. if i set the Preferred Network Type to WCDMA ONLY, it got no signal with just a cross on the signal bar. i have to put it back into GSM ONLY mode to receive signal.if i go out, i can get partial 3G connectivity here and there, but not consistently. sometimes even if i have full 3G bar signals on the status bar, i can not make calls or connect to the internet.i've got this problem probably after i tried to forcibly go into the Phone Info menu.i got repetitive " the process com.android.phone has stopped unexpectedly" promps , and i just ignored it and tried again. now ,2 options are missing from the menu, LTE/WCDMA/GSM and LTE Global.in place of them, it's UNKNOWN. i already tried flashing KDZ package of no avail. Does this mean a hardware malfucntion or software glitch?Please help!Thank you in advance

No one can answer?

freefall12 said:
No one can answer?
Click to expand...
Click to collapse
Ask att store for a different sim card i had lte issues and new sim card helped try that
LG NITRO-N XDA APP

Well you do HAVE GSM only selected. THATS 2G(EDGE)
for 3G you would need to select WCDMA

hyelton said:
Well you do HAVE GSM only selected. THATS 2G(EDGE)
for 3G you would need to select WCDMA
Click to expand...
Click to collapse
^^^So true
LG NITRO-N XDA APP

no, if i select wcdma, i got no signal.it should be hardware problem

[How to] disable LTE on AT&T S3 (you can disable HSPA+ too)

I have read that you can change your APN settings to turn off LTE. However, I found another way (with the help of carefreelife). Use at your own risk! I am not responsible for any harm you may do though it seems fairly safe to me!:
UPDATE: THERE IS NOW AN EASIER METHOD TO DO THIS WITHOUT PULLING THE SIM AND REBOOTING (check out post #47 below or use this link)
http://forum.xda-developers.com/showpost.php?p=37310325&postcount=47
[OLD METHOD]1) With phone on, take off back cover and press your SIM card so it releases from the spring. It won't come all the way out as it's blocked by the battery. This seems fine - I didn't bother trying to force it out as I didn't want to break anything...
2) Once you see the message that the SIM card is removed, go to the dialer and dial *#2263#
3) You should see a menu with band selections. The current setting is "Automatic". If you switch to "GSM All", you will be EDGE (2G). If you switch to "WCDMA All", you will be on HSPA+ (3G, though AT&T and others call it 4G).
4) Press the SIM card back into place until it clicks. For whatever reason the phone will not recognize it until you reboot. Upon reboot you should see your new setting in effect.[/OLD METHOD]
I was attempting to follow this procedure for the S2:
{Trick} Get Around "RAT SELECTION RESTRICTED" on i897 modems! - xda-developers
...but I couldn't get the SIM out easily so I left it in...and followed the steps. It wouldn't recognize that the SIM had been reinserted so I gave up and rebooted...and it worked! No need to mess with airplane mode or anything just follow the steps above.
I was then able to follow the same procedure and turn back on the default setting which was "1) Automatic". After a reboot I am again connected to LTE.
Reason I'm using this: I'm testing a major battery drain issue that might be related to LTE/HSPA+ switching.
Reason you might want this: If you have poor LTE signal or even poor HSPA+ signal and want your phone to stop trying to connect to that network, this will stop it.
UPDATE:
A little bit of bad news here:
I have been on "WCDMA All" (HSPA+ aka 3G4/G, with LTE disabled) for 10 days now with ZERO problems whatsoever.
However, I am pretty sure that whichever you choose, if not "Automatic", you will be locked to ONLY that band:
i.e. if you choose "WCDMA All" you will not only be disabling LTE, but also 2G (EDGE) as well. You may not need it (and if so, it will not effect you) - but if your phone loses the HSPA+ signal, it will not fall back to 2G unless you change the setting.
I tested this theory by setting my phone to "LTE all" and trying to call myself from another phone. The call went straight to my voicemail. LTE is data only (for now) and when you receive a call, it switches to HSPA+. Unfortunately, since I had set my phone to "LTE All", it stayed on LTE and could not receive the call.
This may not be a deal-breaker but it's something to be aware of, for sure. I only tested "LTE All" because it was easy to do so, but I am assuming the same applies for the other settings...only "Automatic" would seem to pick the best available network.
Click to expand...
Click to collapse

Edited OP and changed thread title. Please help me test this. Thanks!

Just out of my curiosity, can you not do this:
settings > wireless and networks > more settings > mobile networks > network mode > GSM/HSPA
I have the Bell version, which is similar to ATT's, wondering if ATT disabled that option.

fortesquieu said:
Just out of my curiosity, can you not do this:
settings > wireless and networks > more settings > mobile networks > network mode > GSM/HSPA
I have the Bell version, which is similar to ATT's, wondering if ATT disabled that option.
Click to expand...
Click to collapse
Yes, it is disabled on AT&T versions. If you try the method I listed above without removing the SIM card, it will be blocked as well.
AT&T does not want us to have any control over which network we connect to. It's been speculated that they want us forced on to LTE to take strain off the HSPA network. Honestly I think that's fine - though I prefer to have a choice - except that I suspect LTE switching is causing my battery drain issue and I need to turn it off in order to test that theory.
http://forum.xda-developers.com/showthread.php?t=1811182

carefreelife at Android Central forums showed me that WCDMA All is the proper setting to disable LTE and stay on HSPA. It's working for me and seems to be perfect!

Curious,why dont u want LTE?
Sent from my SAMSUNG-SGH-I747 using xda premium

bbgt2 said:
Curious,why dont u want LTE?
Click to expand...
Click to collapse
Testing to see if it's causing the battery drain issue described in this thread:
http://forum.xda-developers.com/showthread.php?t=1811182

Oh ok. Cant complain about battery life. Been on stock, rooted stock, CM10 and always the same 14 hours between charges. Heavy user WiFi Twitter exchange etc.
Sent from my SAMSUNG-SGH-I747 using xda premium

bbgt2 said:
Oh ok. Cant complain about battery life. Been on stock, rooted stock, CM10 and always the same 14 hours between charges. Heavy user WiFi Twitter exchange etc.
Click to expand...
Click to collapse
My battery life is great too - there just seems to be a bug that causes it to suddenly become terrible and drain fast until it's rebooted. This is just a method I'm using to test it.
It's possible that disabling LTE can increase battery life but I'm not sure there's any evidence that LTE uses more battery than HSPA+. On older phones the LTE was not integrated into the SoC and thus was a power hog...but it's integrated on the S3.
For users who are on fringe areas and receive poor LTE or HSPA+ coverage...the phone will use extra battery trying to connect and stay connected to those...even if it's [mostly] unsuccessful. Using this method would be a good idea for people who would rather just stay on the bands with strong signal and stop wasting battery trying to get on LTE or HSPA+ fruitlessly.

Thanks a lot for this I've been wanting to switch to 2g only THANKS

Your the man! I've wanted to do this since I got the phone. Is there anyway to use combination bands like in the Captivate?
Sent from my GSIII
---------- Post added at 09:55 AM ---------- Previous post was at 09:52 AM ----------
Woah I just noticed your that guy from the other thread that had some serious battery life issues. Still no luck huh?
Sent from my GSIII

I can't get into the screen.. Always get some error after entering *#2263#

DudeWatsThat said:
Your the man! I've wanted to do this since I got the phone. Is there anyway to use combination bands like in the Captivate?
---------- Post added at 09:55 AM ---------- Previous post was at 09:52 AM ----------
Woah I just noticed your that guy from the other thread that had some serious battery life issues. Still no luck huh?
Click to expand...
Click to collapse
Hey what's up. I don't know what combination bands are - haven't ever used the Captivate.
And yes I'm still working on those battery issues...I'm hoping that THIS fixes it...even though it would meaning losing LTE for the time being...at least I'd know what's causing it!
X10D3 said:
I can't get into the screen.. Always get some error after entering *#2263#
Click to expand...
Click to collapse
What's the error you get? Are you using an AT&T Galaxy S3?

jeffreii said:
Hey what's up. I don't know what combination bands are - haven't ever used the Captivate.
And yes I'm still working on those battery issues...I'm hoping that THIS fixes it...even though it would meaning losing LTE for the time being...at least I'd know what's causing it!
What's the error you get? Are you using an AT&T Galaxy S3?
Click to expand...
Click to collapse
You can mix the different bands between wcdma and gsm and their frequencies,that way you can get the best signal in your area.
How's that LTE test coming?
Sent from my GSIII

Does nothing. When I hit send it just says invalid mmi code.
Sent from my SAMSUNG-SGH-I747 using xda premium

DudeWatsThat said:
You can mix the different bands between wcdma and gsm and their frequencies,that way you can get the best signal in your area.
How's that LTE test coming?
Click to expand...
Click to collapse
I can't say anything for sure until I get about 1 week of uptime with no plummet. It's been stable (battery and signal) since I enabled it, though.
X10D3 said:
Does nothing. When I hit send it just says invalid mmi code.
Click to expand...
Click to collapse
You shouldn't even have to hit send...as soon as you hit the second # it should go straight to the menu.
*#2263#
I can't guarantee this works with any modifications to stock as I have only done it on my unrooted stock AT&T S3.

CM10. I just learned that you can only use dialer codes on stock roms. AOSP roms don't recognize them. There's a small few that work. obviously this one doesn't. Where can I find the APN info?

Nice find!! Works perfectly with my AT&T Galaxy S3. Going to test it out for a few days. I have 4G LTE where I live but when I go to college in the fall there won't be any LTE. This will come in handy!
However, with the WCDMA option enabled, does this mean you only have access to 3G and not 2G? Sometimes when I am in rural areas there is no 3G so I need to use EDGE or GSM. Hopefully with the WCDMA all enabled 2G is still accessible.

X10D3 said:
CM10. I just learned that you can only use dialer codes on stock roms. AOSP roms don't recognize them. There's a small few that work. obviously this one doesn't. Where can I find the APN info?
Click to expand...
Click to collapse
I've seen it here and there - including in my battery plummet thread linked earlier. I first found it mentioned here:
http://forums.androidcentral.com/t-galaxy-s-iii/181957-turning-off-lte.html
ComradeNF said:
Nice find!! Works perfectly with my AT&T Galaxy S3. Going to test it out for a few days. I have 4G LTE where I live but when I go to college in the fall there won't be any LTE. This will come in handy!
However, with the WCDMA option enabled, does this mean you only have access to 3G and not 2G? Sometimes when I am in rural areas there is no 3G so I need to use EDGE or GSM. Hopefully with the WCDMA all enabled 2G is still accessible.
Click to expand...
Click to collapse
That's a great question. I have looked at it like a hierarchy but there's plenty of reason to believe it could be otherwise. There's not really anywhere in Miami I can go that doesn't have really strong HSPA+ so I don't know how I can test it. If anyone can do this test themselves and see what happens when you leave a 3G area please post results here.
Actually, once I am done testing the battery drain I could switch from Automatic to LTE and find somewhere in Miami where there's only 3G and see if it switches down to 3G or just loses signal entirely. Someone could also switch to LTE mode and try to receive a phone call...if it is truly locked on ONLY LTE then it won't be able to take a call...
The more I think about it the more it seems like this could be a major drawback of this method. I look forward to testing this later and hearing what you guys find as well. Thanks!

jeffreii said:
I've seen it here and there - including in my battery plummet thread linked earlier. I first found it mentioned here:
http://forums.androidcentral.com/t-galaxy-s-iii/181957-turning-off-lte.html
That's a great question. I have looked at it like a hierarchy but there's plenty of reason to believe it could be otherwise. There's not really anywhere in Miami I can go that doesn't have really strong HSPA+ so I don't know how I can test it. If anyone can do this test themselves and see what happens when you leave a 3G area please post results here.
Actually, once I am done testing the battery drain I could switch from Automatic to LTE and find somewhere in Miami where there's only 3G and see if it switches down to 3G or just loses signal entirely. Someone could also switch to LTE mode and try to receive a phone call...if it is truly locked on ONLY LTE then it won't be able to take a call...
The more I think about it the more it seems like this could be a major drawback of this method. I look forward to testing this later and hearing what you guys find as well. Thanks!
Click to expand...
Click to collapse
I'd also love to know if 2G works, but I can't while in North California. There isn't a single place within a 20 mile radius of where I live that doesn't have full LTE and HSPA+ coverage since so many people live here. I go to college in a fairly rural area in California though so in late September I'll be able to confirm if we can get 2G with the WCDMA method.

At&t temoraly RAT removal

I just play with my S3 I747 and find out how to temporaly remove RAT restriction.
Click phone then punch code : *#197328640# ->Umts->Debag Screen->Phone Control->Network Lock->Rat_Free_Supporting ON
After you click this you see " Now RAT Free Supporting". Click back button and try setting radio by pressing *#2263#.
RTA will lock back after restarting.

could you explain what "RAT restriction" is and what removing it will provide?

kirkgbr said:
could you explain what "RAT restriction" is and what removing it will provide?
Click to expand...
Click to collapse
Here is a thread that talks about RAT restrictions. It appears to have to do with restricting access to certain bands, but I am swimming in waters that are deeper than my skills will allow.
http://forum.xda-developers.com/showthread.php?t=1189241

norbarb said:
I just play with my S3 I747 and find out how to temporaly remove RAT restriction.
Click phone then punch code : *#197328640# ->Units->Debag Screen->Phone Control->Network Lock->Rat_Free_Supporting ON
After you click this you see " Now RAT Free Supporting". Click back button and try setting radio by pressing *#2263#.
RTA will lock back after restarting.
Click to expand...
Click to collapse
I gonna do a run for this later today to see if it will actually work for allowing band selection and sticking.

It seemed to work for me, but it's only been a couple of minutes so far after turning off LTE. BTW, the first menu is "UMTS", not "Units".
Sent from my SAMSUNG-SGH-I747 using xda app-developers app

Any suggestions on how to make these changes permanent without rooting?

Since there is now a known code to lift restrictions until reboot, I hope some dev will figure out a way on stock based roms (both stock and mods), as well as AOSP based, to make it permanent. I have tried AOKP and CM10 in hopes the LTE and 2G toggles would work but no dice with AT&T SGS3.
Anonymously_Unknown said:
Any suggestions on how to make these changes permanent without rooting?
Click to expand...
Click to collapse
Given the issue at hand, it is most likely a deeply embedded setting that will not be available to standard user base (non rooted), henceforth root access or even on a programming level will be needed to make the necessary changes. How the changes will be made available, if it is done, will depend on what was needed to make it permanent. This raises the question of where is this restriction coded into the AT&T SGS3. Is it firmware, ROM, SIM related, Radio? Seriously doubt it is hardware itself since there are ways to get around the restriction.

larryka said:
It seemed to work for me, but it's only been a couple of minutes so far after turning off LTE. BTW, the first menu is "UMTS", not "Units".
Sent from my SAMSUNG-SGH-I747 using xda app-developers app
Click to expand...
Click to collapse
Yes you are corect. I make correction in OP.

Testing RAT unlock now.
norbarb said:
I just play with my S3 I747 and find out how to temporaly remove RAT restriction.
Click phone then punch code : *#197328640# ->Umts->Debag Screen->Phone Control->Network Lock->Rat_Free_Supporting ON
After you click this you see " Now RAT Free Supporting". Click back button and try setting radio by pressing *#2263#.
RTA will lock back after restarting.
Click to expand...
Click to collapse
Testing this method now. So far I am running on 2G. I will give it at least a couple of hours and will update this post accordingly.
Update: I was messing around and decided to save this USSD (the official name of these secret dialer codes) in my contacts. From dialer you can start pressing *#1 and when it appears just press it. This gives quick access should you need to change radios often. I also want to add that instead of going back into *#2263# you can also select the band from *#197328640#. If you want to change it immediately, then once you get the confirmation "Now RAT Free Supporting" press the menu key on the left of the Home button. Select back and repeat again to go back again. Then, instead of choosing Network Lock choose Network Control-->Band Selection. This takes you to the same menu that *#2263# does and you can select accordingly.
@norbarb...perhaps you can update your OP to reflect that you can stay within the original selection instead of *#2263# and just go back twice to access the band selection. It is just one more way of doing things.
I also did the test of rebooting my phone. As mentioned by norbarb, if you have rebooted the RAT restriction is back in place. Regardless of which option you take to the band selection it will show RAT restriction until you follow the OPs steps again to remove restriction. Have not found a way for permanent removal of the restriction yet (I am optimistic and really want this permanent so I will look very hard to find a solution.). Also when I rebooted I had GSM 2G only selected prior and I kept the option upon reboot so only the RAT restriction is reset...not the network band settings.
Update 2: After 4 hours I am still on 2G Edge. I am in a very good LTE location so this is definitely the most promising outlook. I have found that I despite my love for the look of AOSP roms, the inability to turn on 2G at all will keep me with TW for now. Thankfully I do not mind the look of TW and with root, I can kill the Bloatware. I will look at all of the options in the *#197328640# menus and see if there is anything that may can be applied for permanent access. I also wonder if the secret to overriding the lack of options for network choices in *#*#4636#*#* will be here as well as this would more preferable to shut down LTE only.

aybarrap1 said:
I also did the test of rebooting my phone. As mentioned by norbarb, if you have rebooted the RAT restriction is back in place. Regardless of which option you take to the band selection it will show RAT restriction until you follow the OPs steps again to remove restriction. Have not found a way for permanent removal of the restriction yet (I am optimistic and really want this permanent so I will look very hard to find a solution.). Also when I rebooted I had GSM 2G only selected prior and I kept the option upon reboot so only the RAT restriction is reset...not the network band settings.
Click to expand...
Click to collapse
Same here.
Sent from my SAMSUNG-SGH-I747 using xda premium

Isn't the problem with doing this, say if you disable LTE and only select HSPA, it wont go to any 2G networks if you are out of coverage. Because its not on 'automatic', its on HSPA. So if you are out of a service zone of HSPA, then you dont have anything to fall back to.
If only there was a way to disable LTE, and use the other networks 'automatically'.

geoldr said:
Isn't the problem with doing this, say if you disable LTE and only select HSPA, it wont go to any 2G networks if you are out of coverage. Because its not on 'automatic', its on HSPA. So if you are out of a service zone of HSPA, then you dont have anything to fall back to.
If only there was a way to disable LTE, and use the other networks 'automatically'.
Click to expand...
Click to collapse
That is the problem. However, AT&T in their infinite focus on trying to force users to their networks of choice has purposely had the ability to do network selections disabled. Under normal circumstances in android devices the option of network selection is under settings and mobile networks option. This is removed I am sure at AT&T's request. The other way to access this is to use USSD *#*#4636#*#* in dialer and select "Device Information" which will give you an option to choose a network preference. While the USSD works the option to select network preference does not work.
At least with the option to unlock RAT and using USSD *#2263#, it gives some sort of ability to choose a network. For me this is perfect since I want the 2G only due to poor 3G and LTE signals at work. However you are right that it is not convenient if you just want LTE off. For the moment there is no known way to obtain this option on the AT&T SGS3.

aybarrap1 said:
That is the problem. However, AT&T in their infinite focus on trying to force users to their networks of choice has purposely had the ability to do network selections disabled. Under normal circumstances in android devices the option of network selection is under settings and mobile networks option. This is removed I am sure at AT&T's request. The other way to access this is to use USSD *#*#4636#*#* in dialer and select "Device Information" which will give you an option to choose a network preference. While the USSD works the option to select network preference does not work.
At least with the option to unlock RAT and using USSD *#2263#, it gives some sort of ability to choose a network. For me this is perfect since I want the 2G only due to poor 3G and LTE signals at work. However you are right that it is not convenient if you just want LTE off. For the moment there is no known way to obtain this option on the AT&T SGS3.
Click to expand...
Click to collapse
Yep. I also think it's something to do with AT&T network setup. Because on AOSP ROM's we can't toggle LTE either. But the same ROM on a Canadian model phone will work just fine.
Even though the iphone has an LTE toggle. At least I read somewhere that it does.

geoldr said:
Yep. I also think it's something to do with AT&T network setup. Because on AOSP ROM's we can't toggle LTE either. But the same ROM on a Canadian model phone will work just fine.
Even though the iphone has an LTE toggle. At least I read somewhere that it does.
Click to expand...
Click to collapse
It has nothing to do with the network setup...it is the carrier forcing restrictions on their customers. I have had three other android phones (including my wifes) in the last three years. All of them were restricted from choosing the network from stock rom. The moment I uploaded a ROM such as CM or other AOSP Roms I was magically able to do a network select. I even had to Windows phones (6.1 and 6.5) and both of them were stripped but with some registry edits I was able to add the option back to select between 3G/2G and 2g only. It is AT&T's way and they are notorious for it.
On a side note, I would not be surprised if AT&T is the primary corporate network that pushed for this network SIM lock ruling by the Congressional Librarian. Of all the carriers they have the most to lose.

If you want to select multiple bands and still turn lte off..
http://forum.xda-developers.com/showthread.php?p=37334232
Galaxy S III I747

fmllc said:
If you want to select multiple bands and still turn lte off..
http://forum.xda-developers.com/showthread.php?p=37334232
Galaxy S III I747
Click to expand...
Click to collapse
I have been testing this for the last 4 hours and it does seem to work. Went to 2g only area and it switched perfectly to 2G and reverted back to 3g when I left the area. However I am not able to do GSM ONLY (2G only) using this method. You will have to follow the instructions on this thread for that.
Sent from my SAMSUNG-SGH-I747 using xda app-developers app

Click back button and try setting radio by pressing *#2263#.
norbarb said:
I just play with my S3 I747 and find out how to temporaly remove RAT restriction.
Click phone then punch code : *#197328640# ->Umts->Debag Screen->Phone Control->Network Lock->Rat_Free_Supporting ON
After you click this you see " Now RAT Free Supporting". Click back button and try setting radio by pressing *#2263#.
RTA will lock back after restarting.
Click to expand...
Click to collapse
How to set radio by pressing *#2263#?
And what is RTA will lock back after restarting?

So what is the benefit of the ability to change bands?

OKAstro said:
So what is the benefit of the ability to change bands?
Click to expand...
Click to collapse
It could result in battery savings and reduced dropped calls. For instance, I am often in and out of areas with little to no bandwidths under LTE. At default, my phone would always looking for an LTE signal which means my battery takes a pounding. By having my phone only look for 2G/3G, I do not take as large of a battery hit. Besides that, LTE does consume more power. For the most part I leave my phone with LTE off because the data speed is not crucial for me. At home I have a really fast WiFi network so it is better to be on it anyway while at home.

aybarrap1 said:
It could result in battery savings and reduced dropped calls. For instance, I am often in and out of areas with little to no bandwidths under LTE. At default, my phone would always looking for an LTE signal which means my battery takes a pounding. By having my phone only look for 2G/3G, I do not take as large of a battery hit. Besides that, LTE does consume more power. For the most part I leave my phone with LTE off because the data speed is not crucial for me. At home I have a really fast WiFi network so it is better to be on it anyway while at home.
Click to expand...
Click to collapse
OK Thanks. But under Settings/More Networks/Mobile Networks/Network Mode there are 13 "band" combination choices. Do those choices not provide what you''re looking for (i.e.2G/3G)?
I've never changed mine, so I'm curious

Can not connect to 4G/3G.

Hello there, I'm in need of your help again.
My SGH-M919 has a problem, it cannot connect to 3G/LTE (Not even EDGE). My carrier uses the 850 mHz band for GSM and 1900 mHz for UMTS, so the phone should be able to use them. The thing is, it doesn't. It only connects to GPRS and the signal is very erratic and weak (Usually 2-3 bars). Sometimes I get SMSs from my carrier saying that I missed like 5 calls when my phone never rang once. I live in a zone with good 3G coverage, so it's not the signal.
I'm currently rooted on Android 4.4.4 (NH7). I already tried selecting "1900 WCDMA" in the *#2263# service menu but that only causes the phone to lose all the signal (And it's a problem to change it back, without signal the service menu doesn't work and I cannot change the Network Mode in Settings).
I've tried to select "WCDMA only" mode before, but my signal just goes to zero (The circle with the slash) before changing back to "LTE/WCDMA/GSM (Auto connect)" automatically.
I also cannot use the Network Operators option. Using "Search now" makes it search for a few seconds before showing the message "Error while searching for networks". The "Select automatically" one shows the message "Unable to connect. Try later" and then connects back to my carrier (Movistar)
My APNs are configured (They did it themselves when I inserted the SIM, but I've configured them manually before). The SIM card works, I tried it in another phone and it got 3G immediately, I also tried another SIM card on the GS4, but the result was the same. Someone told me to upgrade to the latest firmware (NK2) while someone else told me to flash the MDL modem. (Is that even possible? I read something about KNOX blocking all downgrades after 4.3).
Since I couldn't find any direct solution to the problem, I'm recurring to you.
Thanks.
P.S: I didn't change the LTE Band Preference option in the Service Menu because the last time someone messed with it, my IMEI/Baseband went completely nuts, I thought the EFS got corrupted, but they magically appeared everytime I enabled the Airplane Mode (So I was able to select Automatic in the ServiceMenu and they got fixed). Also, I don't live in a LTE area although once during a very strong thunderstorm, I got 4G for a few minutes before going back to G).

*bump*
Any ideas?

Did you put a check mark in data roaming?

Shortbus-Driver said:
Did you put a check mark in data roaming?
Click to expand...
Click to collapse
I've tried with and without it, it doesn't make a difference anyway.

Does it show you have an ìmei # other than all zeros?
Don't post it just a yes or no.

Shortbus-Driver said:
Does it show you have an ìmei # other than all zeros?
Don't post it just a yes or no.
Click to expand...
Click to collapse
My IMEI is fine, the phone connects to the carrier network but it stays on GPRS (and the signal is always dropping)

Update to full NK2 firmware and see if that will fix it

serio22 said:
Update to full NK2 firmware and see if that will fix it
Click to expand...
Click to collapse
I'll try that later. Will I have to re-root and re-install TWRP after flashing NK2?

I have a similar problem with my M919 on the Tmobile network. Using the *#2263# menu I can not get mine to work on WCDMA (4G) either. I can chose GSM /LTE only and my phone works normally but no 4G signal. If I chose WCDMA I get no signal. I can see it trying to connect and immediately dropping the signal. If I choose any option with WCDMA included it has erratic signal and will lose the signal most of the time when I try to make a call. So basically I have the choices of GSM only or GSM/LTE only. Before I discovered the secret menu I was stuck with GSM only in the phone's settings. This has been going on for months. Tmobile changed my SIM card and it didn't help. I've rooted and unrooted my phone (using autoroot) and even tried different modems (even worse signals) and now am back to stock rooted NK2 firmware and modem. I have given up and decided to get another phone (not an S4). My wife's S3 gets great 4G signals in the same location by the way. I wonder if anyone knows why our phones can't use 4G. I am beginning to think it's a hardware problem but I'm way out of warranty on mine.

Strange bug: Data (LTE) is fine but no call or sms

I am using a HTC 10 phone au kddi Japan variant. Got success in converting the phone to international but have been rocking custom ROM for a while already now. Bootloader unlocked, S-OFF (obviously). Been running the custom ROM Viper ROM ok for a while but when I converted to the WWE this strange bug happened. I got data, LTE, good connection but no call or sms and it said No service despite the carrier showing up in the menu. Huge thanks if anyone can help me

I got this OP3 that made me change it to the HTC 10. The Problem of it may give you an explanation.
It couldnt Lock signal on LTE and was returning to Edge So you had to press *#*#4636#*#* and select the Network type to LTE only.
However although the phone locked LTE for good then it couldnt make any phone calls or txt msg.
I had to choose LTE/CDMA or LTE/GSM
In Order to change while in call to Edge or "H+" Network.
I guess by that we understand that LTE is only for DATA and not for Voice calls and txts...?
Hope i helped...

kanth1991 said:
I got this OP3 that made me change it to the HTC 10. The Problem of it may give you an explanation.
It couldnt Lock signal on LTE and was returning to Edge So you had to press *#*#4636#*#* and select the Network type to LTE only.
However although the phone locked LTE for good then it couldnt make any phone calls or txt msg.
I had to choose LTE/CDMA or LTE/GSM
In Order to change while in call to Edge or "H+" Network.
I guess by that we understand that LTE is only for DATA and not for Voice calls and txts...?
Hope i helped...
Click to expand...
Click to collapse
Yeah, I tried your method but it didn't work. Don't really understand why that happen tho because if I have the right radio to have LTE then why can't I do call?