Database Users

[Q] s4 GT-I9505 missing DC-HSDPA/LTE

Hello guys,So im with three.uk they dont do LTE yet but they r about to roll it out very soon however they do DC-HSDPA and im in area where i should be getting it sadly im not getting it for some reason top of the screen shows only H+(mostly) sometimes H and 3G. If i go to connections->More Networks-> Mobile Networks -> Network mode i only get WCDMA/GSM(auto connect) or WCDMA only so this is what i get. I was reading that there is some problem with s4's shipped from korea and people advice to flash to unbranded stock well one was australian so i even flashed to australian firmware even to getman firmware so far no luck no lte in options not detecting DC-HSDPA just after flashing to getman/australian firmware i got an extra option in network mode and it is gsm only plus the other two i said before. So my question is how i could get this DC-HSDPA working and what indicator top of the screen will show instead of h+ will it show DC ? i was trying to find answers but no luck so far please help me outKind rengards Martin

hotelarzm said:
Hello guys,So im with three.uk they dont do LTE yet but they r about to roll it out very soon however they do DC-HSDPA and im in area where i should be getting it sadly im not getting it for some reason top of the screen shows only H+(mostly) sometimes H and 3G. If i go to connections->More Networks-> Mobile Networks -> Network mode i only get WCDMA/GSM(auto connect) or WCDMA only so this is what i get. I was reading that there is some problem with s4's shipped from korea and people advice to flash to unbranded stock well one was australian so i even flashed to australian firmware even to getman firmware so far no luck no lte in options not detecting DC-HSDPA just after flashing to getman/australian firmware i got an extra option in network mode and it is gsm only plus the other two i said before. So my question is how i could get this DC-HSDPA working and what indicator top of the screen will show instead of h+ will it show DC ? i was trying to find answers but no luck so far please help me outKind rengards Martin
Click to expand...
Click to collapse
Hi,
H+ will still display on your signal strength indicator, as DC-HSDPA is just a variant of the HSPA network system. to force the internet to always connect to a higher speed network set it to WCDMA Only.
There is no DC-HSDPA or HSDPA in the network selection, it is tied to the WCDMA system.

vertcam9 said:
Hi,
H+ will still display on your signal strength indicator, as DC-HSDPA is just a variant of the HSPA network system. to force the internet to always connect to a higher speed network set it to WCDMA Only.
There is no DC-HSDPA or HSDPA in the network selection, it is tied to the WCDMA system.
Click to expand...
Click to collapse
Thank you very much mate I was looking everywhere to find de answer. Anyways please id like to ask you if ther is any way to check if im actually connected to DC-HSDPA well im getting speeds up to 29mb/s average is rather 10-15 depends. And once my network gonna realise lte will dat option apear in setting to use it ?

hotelarzm said:
Thank you very much mate I was looking everywhere to find de answer. Anyways please id like to ask you if ther is any way to check if im actually connected to DC-HSDPA well im getting speeds up to 29mb/s average is rather 10-15 depends. And once my network gonna realise lte will dat option apear in setting to use it ?
Click to expand...
Click to collapse
I've tried many apps to find out if im on threes dc-hspa network to no avail. But I now know how by typing *#0011# into keypad and it displays the network mode including dc-hspa

chrizhaynes said:
I've tried many apps to find out if im on threes dc-hspa network to no avail. But I now know how by typing *#0011# into keypad and it displays the network mode including dc-hspa
Click to expand...
Click to collapse
Root Explorer (or another), and go to data/property.
select persist.radio.lteon , edit it with a text editor and change the value from false to true.
Save changes, reboot and enjoy
bye to all.

ilpres said:
Root Explorer (or another), and go to data/property.
select persist.radio.lteon , edit it with a text editor and change the value from false to true.
Save changes, reboot and enjoy
bye to all.
Click to expand...
Click to collapse
Sorry to bump this up, but how does persist.radio.lteon show you DC-HSDPA status in the notificar bar?

nellisere said:
Sorry to bump this up, but how does persist.radio.lteon show you DC-HSDPA status in the notificar bar?
Click to expand...
Click to collapse
I can't answer your question because there's no 4G signal where i live , sorry ....
it was only the solution for who has this problem:
If i go to connections->More Networks-> Mobile Networks -> Network mode i only get WCDMA/GSM(auto connect) or WCDMA only so this is what i get.
Click to expand...
Click to collapse

This isn't about 4G? It's about DC-HSDPA.
Sent from my GT-I9505 using xda app-developers app

have problem after open line
Hi is anybody here in Philippines who have the same issue with me.
i have samsung galaxy s4 i9505 which is smart network lock.
i brought my phone to technician to let it open line,
it was then opened to my globe line but my problem is i barely get an H or H+ data connection,
when i went back to the technician and asked the problem i got after they open it, he said its normal..
am i getting the right answer it is normal to have it for opening other network line? thx.

[Q] Is it possible to force HSPA or HSPA+ and disable LTE?

G2 seems to have worse LTE reception compared to few other devices I had, is there anyway to disable LTE and go down to HSPA or HSPA+?
I know my area has terrible LTE coverage, but for some reason it sticks to LTE even if it means I am forced to 0.3mbps speeds! Ouch.

hydeah said:
G2 seems to have worse LTE reception compared to few other devices I had, is there anyway to disable LTE and go down to HSPA or HSPA+?
I know my area has terrible LTE coverage, but for some reason it sticks to LTE even if it means I am forced to 0.3mbps speeds! Ouch.
Click to expand...
Click to collapse
You can disable LTE from the service menu,use the code 5457#*(your phone model here)# And you will find an option there with the bands to do so.You can enable only the ones you want and dissable all others.Dont change anything else tho.I cant tell you exactly where you will find it cause the menu is slightly different for every variant it seems.

woof123 said:
You can disable LTE from the service menu,use the code 5457#*(your phone model here)# And you will find an option there with the bands to do so.You can enable only the ones you want and dissable all others.Dont change anything else tho.I cant tell you exactly where you will find it cause the menu is slightly different for every variant it seems.
Click to expand...
Click to collapse
Thank you so much, I remember now people were running this trick on Nexus 4, but sadly it did not work. When you say Model here, I just put numbers only right? I got the D800 from AT&T, in dialer I just hit 5457#*800# and hit call, nothing happens, I get invalid MMI error. I tried 5457#800# no luck.
However, using your suggestion, I found the code to access service menu, but it wasn't as clear as I hoped it would be so I did not touch anything.
Code:
AT&T LG G2 D800 Service Menu: 3845#*800#
T-Mobile LG G2 D801 Service Menu: 3845#*801#
Verizon LG G2 VS980 Service Menu: 3845#*980#
Sprint LG G2 LS980 Service Menu: 3845#*980#
I expected on/off switches, but there is WDCMA-Only, LTE-Only, and nothing else. There is no HSPA or HSPA+ only or any switch, and I don't want to hit LTE only assuming that will limit the reception to LTE and I will get stuck with no coverage when there is no LTE.

On Sprint, I can go into data settings via dialer (##3282#), and edit LTE screen (requires service code). From there, I can disable LTE and force CDMA/EvDo. Of course, this is on Sprint variant, not sure how AT&T/T-Mobile does it or whichever carrier you're on.

Ascertion said:
On Sprint, I can go into data settings via dialer (##3282#), and edit LTE screen (requires service code). From there, I can disable LTE and force CDMA/EvDo. Of course, this is on Sprint variant, not sure how AT&T/T-Mobile does it or whichever carrier you're on.
Click to expand...
Click to collapse
I am on ATT and I can't find this setting anywhere.
Sent from my LG-D800

I also tried *#*#4636#*#* which does not let me go into OEM-Info or any Radio selection.
Why does AT&T do this!?

I believe if you go into settings and go into the mobile networks menu, there is a menu that allows you to choose whether the phone will go into LTE if available or just stay on 4G HSPA+. I'm getting my G2 tomorrow, so I don't remember exactly how I did it when I played with it in the store. If you can't find it, I'll let you know what it is once I get my phone. This is with the T-Mobile G2.

Howie Dub said:
I believe if you go into settings and go into the mobile networks menu, there is a menu that allows you to choose whether the phone will go into LTE if available or just stay on 4G HSPA+. I'm getting my G2 tomorrow, so I don't remember exactly how I did it when I played with it in the store. If you can't find it, I'll let you know what it is once I get my phone. This is with the T-Mobile G2.
Click to expand...
Click to collapse
In order of Nice to Naughty,
Sprint
T-Mobile
AT&T
Verizon (wayyyyy low in the list, naughtiest)
So, considering above, I am pretty sure A&T disabled that menu you are referring to (In Mobile Networks) some confirmed it working on Sprint, but I don't think it is available on AT&T. I am stuck with LTE.

hydeah said:
In order of Nice to Naughty,
Sprint
T-Mobile
AT&T
Verizon (wayyyyy low in the list, naughtiest)
So, considering above, I am pretty sure A&T disabled that menu you are referring to (In Mobile Networks) some confirmed it working on Sprint, but I don't think it is available on AT&T. I am stuck with LTE.
Click to expand...
Click to collapse
Sorry, missed it earlier when you said you were on AT&T. Are you able to go to Settings > Tethering & networks > Mobile networks > Network mode? With the T-Mobile version, there's gsm/wcdma/lte auto, gsm/cdma auto, wcdma only, and gsm only selections under the Network Mode menu. That would really suck if they diabled that setting. I'm assuming you're on stock unrooted.

Howie Dub said:
Sorry, missed it earlier when you said you were on AT&T. Are you able to go to Settings > Tethering & networks > Mobile networks > Network mode? With the T-Mobile version, there's gsm/wcdma/lte auto, gsm/cdma auto, wcdma only, and gsm only selections under the Network Mode menu. That would really suck if they diabled that setting. I'm assuming you're on stock unrooted.
Click to expand...
Click to collapse
Nope, it's not there.
ATT disabled it.
Sent from my LG-D800

Possible solution for your case: http://forum.xda-developers.com/showthread.php?t=2361631#post60145354

Ascertion said:
On Sprint, I can go into data settings via dialer (##3282#), and edit LTE screen (requires service code). From there, I can disable LTE and force CDMA/EvDo. Of course, this is on Sprint variant, not sure how AT&T/T-Mobile does it or whichever carrier you're on.
Click to expand...
Click to collapse
Where i can get this "service code"? I just want do the oposite, i want to activate LTE.

Did you ever figure this out?

Superorb said:
Did you ever figure this out?
Click to expand...
Click to collapse
Service code for the d800 is 3845#*800#
Go to LTE settings, modem setting, then select RAT then you can force what ever mode you want.
Sent from my LG-D800 using Tapatalk

xmayhemreturnsx said:
Service code for the d800 is 3845#*800#
Go to LTE settings, modem setting, then select RAT then you can force what ever mode you want.
Sent from my LG-D800 using Tapatalk
Click to expand...
Click to collapse
There's no RAT selection for me under the LTE modem settings. I have LTE Band Selection, VoLTE Radio, Null Integrity, and LTE-A CA.

Superorb said:
There's no RAT selection for me under the LTE modem settings. I have LTE Band Selection, VoLTE Radio, Null Integrity, and LTE-A CA.
Click to expand...
Click to collapse
Try using a custom ROM such as cloudy g2 I know it works there because that is what I am using
Sent from my LG-D800 using Tapatalk

xmayhemreturnsx said:
Try using a custom ROM such as cloudy g2 I know it works there because that is what I am using
Sent from my LG-D800 using Tapatalk
Click to expand...
Click to collapse
Alright, thanks.

I use this tool from the market to force the band(s) I want...
https://play.google.com/store/apps/details?id=com.tapbase.LTEswitcher
I'm on Cloudy 2.2 and it works like a charm.

nomad4ever said:
I use this tool from the market to force the band(s) I want...
https://play.google.com/store/apps/details?id=com.tapbase.LTEswitcher
I'm on Cloudy 2.2 and it works like a charm.
Click to expand...
Click to collapse
Thanks!

[Q] LTE in G900FD

I cant see LTE in my mobile networks mode in G900FD
it has only:
WCDMA/GSM (auto connect)
WCDMA only
GSM only
can anybody help me to turn my LTE on ?

rmn3432 said:
I cant see LTE in my mobile networks mode in G900FD
it has only:
WCDMA/GSM (auto connect)
WCDMA only
GSM only
can anybody help me to turn my LTE on ?
Click to expand...
Click to collapse
Well if your APN settings are allright you either have no LTE coverage or it isn`t available at your provider. LTE should be activated automaticaly if available.

gee2012 said:
Well if your APN settings are allright you either have no LTE coverage or it isn`t available at your provider. LTE should be activated automaticaly if available.
Click to expand...
Click to collapse
my APN setting is right and i am in LTE coverage (my galaxy s3 9305 has LTE/WCDMA/GSM mode and connect to LTE network) but it has not any LTE in setting and i cant connect to LTE
I update to G900FDXXU1ANH2 to resolve this problem but it doesnt resolved

rmn3432 said:
my APN setting is right and i am in LTE coverage (my galaxy s3 9305 has LTE/WCDMA/GSM mode and connect to LTE network) but it has not any LTE in setting and i cant connect to LTE
I update to G900FDXXU1ANH2 to resolve this problem but it doesnt resolved
Click to expand...
Click to collapse
Better contact your provider. Does the G900FD support your providers LTE band/frequency? I would check that first.

gee2012 said:
Better contact your provider. Does the G900FD support your providers LTE band/frequency? I would check that first.
Click to expand...
Click to collapse
i think that i have to see LTE in networks if there is no sim card registered in the phone
am i right ?

rmn3432 said:
i think that i have to see LTE in networks if there is no sim card registered in the phone
am i right ?
Click to expand...
Click to collapse
That would be impossible as you cannot connect to the network without a simcard

gee2012 said:
That would be impossible as you cannot connect to the network without a simcard
Click to expand...
Click to collapse
and i cant go to networks too

rmn3432 said:
and i cant go to networks too
Click to expand...
Click to collapse
I`am starting to think that the G900FD supports different LTE bands then the G900F because it is build for a different region. Its mainly sold in the far east as i can see so far. Better Google to find the specs and the phones supported LTE bands. You may not be able to get LTE with your device i`am afraid. Good luck mate.

gee2012 said:
I`am starting to think that the G900FD supports different LTE bands then the G900F because it is build for a different region. Its mainly sold in the far east as i can see so far. Better Google to find the specs and the phones supported LTE bands. You may not be able to get LTE with your device i`am afraid. Good luck mate.
Click to expand...
Click to collapse
you are right
i have to check frequency bands in my phone becuse i buy this phone from UAE and i dont know that LTE bands are the same as my operators lte frequency bands

You should see LTE on sim2 only. Not Sim 1 .

rmn3432 said:
you are right
i have to check frequency bands in my phone becuse i buy this phone from UAE and i dont know that LTE bands are the same as my operators lte frequency bands
Click to expand...
Click to collapse
i am planning to buy this phone, can anybody share the supported LTE bands or networks where LTE has been used successfully

Similar problem with me, could anybody share some insight

Hi guys
I also had the issue of LTE not being selectable on my S5 Duos - here's my experiences.
Firstly I tried putting another carriers SIM into the phone, and noticed that LTE -was- selectable, but upon putting my own SIM back in, it again wasn't. HOWEVER - after putting my own SIM back in after using LTE on the other SIM, the phone automatically connected to LTE/4G even though WCDMA (auto) was selected! Very odd.
To permanently fix this here was my method -
My phone was shipped with ANF7 firmware, which was patched to overcome the kernel vulnerability Towelroot uses to gain root. I flashed my phone with ODIN back to ANF6 firmware, applied towelroot V3, then installed root browser and edited the system file data >property>persist.radio.lteon and changed the value from false to true, and rebooted the phone. LTE is now selectable!
:EDIT: Upgrading again to ANF7 broke the selection, but it still connected to LTE automatically... So odd.

rmn3432 said:
I cant see LTE in my mobile networks mode in G900FD
it has only:
WCDMA/GSM (auto connect)
WCDMA only
GSM only
can anybody help me to turn my LTE on ?
Click to expand...
Click to collapse
Hi,
I had the same issue as yours. You can either fix it by a method explained here at XDA and it involves rooting the device. However I fixed my issue by flashing the latest firmware "G900FDXXU1ANJ2" for the month of November via Odin and now I can see the LTE/WCDMA/GSM option on sim 1. Hope this helps

[N9005] 4G was working. Now it's not. Help!

One morning when I woke up my N9005 was stuck in the boot animation. I waited a while but I had to hold the power button in to force a power off. Since then I have had no 4G at all. 4G was working before this. Can anyone suggest anything that might re-enable 4G?

Contact your operator.

AndrOmega said:
Contact your operator.
Click to expand...
Click to collapse
It's nothing to do with my operator. I have tried two different SIMs from two different operators that both worked with 4G before. I own the phone, it came from eBay but as I said it was doing 4G before.
--
Brian G. (In the UK)

More info
See attached screenshots:
I'm not sure why "Available CSC Codes" is blank.
Could that be part of the problem?

bdg2 said:
See attached screenshots:
I'm not sure why "Available CSC Codes" is blank.
Could that be part of the problem?
Click to expand...
Click to collapse
Reflash your phone with the latest version from sam mobile

AndrOmega said:
Reflash your phone with the latest version from sam mobile
Click to expand...
Click to collapse
I already did that. At least I think I did it right. Afterwards it started up exactly as usual. There was no extra optimising apps like after an upgrade. I used Odin. Do you think I did it right? I also tried a factory reset. Still no 4G.
--
Brian G. (In the UK)

bdg2 said:
I already did that. At least I think I did it right. Afterwards it started up exactly as usual. There was no extra optimising apps like after an upgrade. I used Odin. Do you think I did it right? I also tried a factory reset. Still no 4G.
--
Brian G. (In the UK)
Click to expand...
Click to collapse
I can't help anyhow but what I do if I loose LTE connection I force it back with 4G Switcher app. You choose LTE only and it should connect (though I can't call or receive calls in LTE only mode) so what I do is when LTE conects I swap mode to LTE/Gsm auto and LTE stays as long as I'm on LTE area (until I somehow loose LTE again in area where LTE is available). Try that out maybe it will drive you to some new conclusions what the issue may be.

boloboss said:
I can't help anyhow but what I do if I loose LTE connection I force it back with 4G Switcher app. You choose LTE only and it should connect (though I can't call or receive calls in LTE only mode) so what I do is when LTE conects I swap mode to LTE/Gsm auto and LTE stays as long as I'm on LTE area (until I somehow loose LTE again in area where LTE is available). Try that out maybe it will drive you to some new conclusions what the issue may be.
Click to expand...
Click to collapse
Do you mean this one?
https://play.google.com/store/apps/details?id=com.tapbase.LTEswitcher
It says it's incompatible with my device!
Also it sounds like you had the situation where you lose the ability to select "LTE/WCDMA/GSM (auto connect)" and can only select "WCDMS/GSM (auto connect)". I have not lost the ability to select "LTE/WCDMA/GSM (auto connect)".

bdg2 said:
Do you mean this one?
https://play.google.com/store/apps/details?id=com.tapbase.LTEswitcher
It says it's incompatible with my device!
Also it sounds like you had the situation where you lose the ability to select "LTE/WCDMA/GSM (auto connect)" and can only select "WCDMS/GSM (auto connect)". I have not lost the ability to select "LTE/WCDMA/GSM (auto connect)".
Click to expand...
Click to collapse
1- Yes, that's the one
2- It works on my Note 3
3- As to your assumption...well I'm not sure what you talk about. I'll explain my issue. Sometimes when I'm on LTE available area my phone connects to HDSPA+. Then I do what I described (I choose LTE on this app to force connect via LTE). I don't know do I loose "ability to select "LTE/WCDMA/GSM (auto connect)" as you said. To be specific what are you reffering with it to? To phone settings or to this app setiings? All I can choose on phone settings is 2g,3g and 4g. There's no X/Y auto connect. This option is in apps settings though and I don't really care what I loose there as long as it works when I want to force LTE with it. I'm courius why it's not compatible with your device. What phone do you have?
All in all in the end use of this app won't solve your issue permanently but with it you could make sure LTE receiver and LTE drivers on your phone system works. Then you could dig down further. You would just know that LTE works at all on your phone.

boloboss said:
1- Yes, that's the one
2- It works on my Note 3
3- As to your assumption...well I'm not sure what you talk about. I'll explain my issue. Sometimes when I'm on LTE available area my phone connects to HDSPA+. Then I do what I described (I choose LTE on this app to force connect via LTE). I don't know do I loose "ability to select "LTE/WCDMA/GSM (auto connect)" as you said. To be specific what are you reffering with it to? To phone settings or to this app setiings? All I can choose on phone settings is 2g,3g and 4g. There's no X/Y auto connect. This option is in apps settings though and I don't really care what I loose there as long as it works when I want to force LTE with it. I'm courius why it's not compatible with your device. What phone do you have?
All in all in the end use of this app won't solve your issue permanently but with it you could make sure LTE receiver and LTE drivers on your phone system works. Then you could dig down further. You would just know that LTE works at all on your phone.
Click to expand...
Click to collapse
"LTE/WCDMA/GSM (auto connect)" is a setting on my phone. See my Screenshot_A.png above. It tells the phone to automatically switch between LTE (4G), WCDMA (3G) and GSM (2G). The other choices don't include 4G. I reach it by Settings / Connections / More networks / Mobile networks / Network mode.
Is you phone rooted? Mine isn't. Could that be why the app doesn't like my phone?

Further info: apparently the phone was originally Portuguese but has been flashed with UK BTU firmware. However as I said before it definitely did do 4G when I first got it. Samsung tried to tell me there was some kind of update that might has disabled 4G in the UK for this device. Sounds like a made up excuse to me.
--
Brian G. (In the UK)

What baseband and bootloader are on the phone? Do they match the uk firmware?

audit13 said:
What baseband and bootloader are on the phone? Do they match the uk firmware?
Click to expand...
Click to collapse
I think so. Isn't the info in my screenshots of Samsung Phone Info Plus (in a post a further up the thread) enough to confirm?
If not could you guide me how I can check. Thanks.

I compared it to uk firmware on sammobile.com and it seems to match. Maybe you need to flash the entire uk firmware again in Odin?

Still same. I've taken it to a Samsung service centre now.
--
Brian G. (In the UK)

bdg2 said:
Still same. I've taken it to a Samsung service centre now.
--
Brian G. (In the UK)
Click to expand...
Click to collapse
It's back, and it's working fine now. And, nice surprise, it was apparently just inside it's guarantee period so I didn't have to pay.
I'm not sure what they did but it's back on Portuguese firmware, which doesn't seem to matter, I just select English (UK) after factory reset and all is well.
Oddly the WiFi adapter has a new MAC address but the magnetic field sensor must be the original one since it's calibration is way off exactly as it was originally. (You have to calibrate it after every reboot by rotating the device in three axis if you want compass functions to work).
--
Brian G. (In the UK)

Note fe won't get 4g lte. 3g only.

Hi there! My note fe can only get 3g. My model is n935k and I am a current an ATT user. I tried to force the phone to LTE only but when I did that, the phone was totally out of service. No network and no call service. I thought note fe LTE band will be worldwide, so is there any setting that I missed?

Tim007super said:
Hi there! My note fe can only get 3g. My model is n935k and I am a current an ATT user. I tried to force the phone to LTE only but when I did that, the phone was totally out of service. No network and no call service. I thought note fe LTE band will be worldwide, so is there any setting that I missed?
Click to expand...
Click to collapse
1. make sure your APN is ATT Nextgenphone (should have been auto-configured when you booted phone the first time) 2. Try reseting your network settings (this will remove bluetooth and wifi settings) settings->general management->reset->reset network settings and/or 3.Call ATT and make sure your account is (still) provisioned for LTE. i have the same model as you do and have no problem getting LTE service. picture below shows i'm connecting to LTE Bands 2, 4, 5 & 17.

I reset the network setting and still doesn't work. The apn is nextgenphone.

cortez.i said:
1. make sure your APN is ATT Nextgenphone (should have been auto-configured when you booted phone the first time) 2. Try reseting your network settings (this will remove bluetooth and wifi settings) settings->general management->reset->reset network settings and/or 3.Call ATT and make sure your account is (still) provisioned for LTE. i have the same model as you do and have no problem getting LTE service. picture below shows i'm connecting to LTE Bands 2, 4, 5 & 17.
Click to expand...
Click to collapse
May I see your apn setting?

fellow note fe user in north america here.
no issue with lte. but @cortez.i what LTE log app is that? and also how did you customize your icons on the status bar?

LTE Discovery from the play store... Substratum theme for Samsung (Swift Dark) for icons.

Tim007super said:
May I see your apn setting?
Click to expand...
Click to collapse
It's the same as on att website. Pic attached

cortez.i said:
It's the same as on att website. Pic attached
Click to expand...
Click to collapse
I tried ways you told me and the phone is still connected to 3g

cortez.i said:
It's the same as on att website. Pic attached
Click to expand...
Click to collapse
And I have tried some app like force phone to switch to lte. After forcing the phone to lte, the phone signal is lost and become emergency call only.

I had the same exact problem and I'm also on AT&T. Restarting the phone fixed it, at least for now.

mb523 said:
I had the same exact problem and I'm also on AT&T. Restarting the phone fixed it, at least for now.
Click to expand...
Click to collapse
sigh, I restarted it and it still showed 3g

Tim007super said:
sigh, I restarted it and it still showed 3g
Click to expand...
Click to collapse
if you haven't done this already, consider trying another SIM. I'd also post screen shots of your configurations; could be something we've missed in our attempts to help you resolve your issues.