First let me state I've searched for answers for a week, tried things to no resolve. This is all because my T-Mobile phone wasn't getting at&t 3G.
I purchased an unlocked, rooted Samsung Vibrant. Specs below:
Firmware: 2.2
Kernel: 2.6.32.9
Build: Bionix-v 1.2.1 By Team Whiskey
I did the following:
1. Remove SIM card
2. After "SIM card recoverd." message, dial *#2263#
4. Select option 4 - Combi bands
5. Select option 8 - WCDMA 850
6. Select Menu, Back
Now when i start/restart my phone, it takes longer to get to home screen (i see the "Team Whiskey" refreshing 2 to 4 times before getting to the home screen).
And I'm still only getting EDGE (E), not 3G.
I've downloaded Speedtest.net and performed a test - results:
Download: .04Mbps
Upload: .02Mbps
So I'm looking for help/guidance on the acquiring 3G and on the start/restart issue. I live in Niagara Falls, NY.
mattband83 said:
First let me state I've searched for answers for a week, tried things to no resolve. This is all because my T-Mobile phone wasn't getting at&t 3G.
I purchased an unlocked, rooted Samsung Vibrant. Specs below:
Firmware: 2.2
Kernel: 2.6.32.9
Build: Bionix-v 1.2.1 By Team Whiskey
I did the following:
1. Remove SIM card
2. After "SIM card recoverd." message, dial *#2263#
4. Select option 4 - Combi bands
5. Select option 8 - WCDMA 850
6. Select Menu, Back
Now when i start/restart my phone, it takes longer to get to home screen (i see the "Team Whiskey" refreshing 2 to 4 times before getting to the home screen).
And I'm still only getting EDGE (E), not 3G.
I've downloaded Speedtest.net and performed a test - results:
Download: .04Mbps
Upload: .02Mbps
So I'm looking for help/guidance on the acquiring 3G and on the start/restart issue. I live in Niagara Falls, NY.
Click to expand...
Click to collapse
Yeah, apparently even though it says WCDMA the 850 band is only EDGE. 1900 is the 3G band on the Vibrant for AT&T. So if you're in an area with only 850, or if 1900 gets full and you get bumped down then you won't get 3G. That's the downside of this phone versus the Captivate.
Thanks, and thoughts on the start up issue? It wasn't like that until i did the steps as noted above.
mattband83 said:
Thanks, and thoughts on the start up issue? It wasn't like that until i did the steps as noted above.
Click to expand...
Click to collapse
Try restarting it again. See if the reboot is back to normal. I think it should.
still refreshed 3 or 4 times but it seems to be faster.
so the only fix for the 3g is to get a captivate? It's with my area? Cause i have seen sites that state the vibrant should be able to get att 3g.
thanks for the help.
So i'm noticing sometimes when i restart my phone, i see the H for 3g but then it turns into E for edge. Thoughts?
Also, when i do the speedtest while on EDGE - shouldn't it be faster than what i've been getting, which is usually 60kbps down and 80kbps up.
The best way probably to test is your sim card in another vibrant. maybe yours is bad. I don't know. An at&t phone would be a better way to ensure you get the right bands. If we didn't have such great devs and I wasn't in a good area for 1900 then I'd switch. I am also to lazy to switch.
Sent from my Vibrant using Tapatalk Pro.
Dude leave your SIM in.
I did all those with my friends SIM in and it worked.
Master&Slave™ said:
Dude leave your SIM in.
I did all those with my friends SIM in and it worked.
Click to expand...
Click to collapse
I'm sorry - what worked?
Related
I'm in a 3 Vibrant household. The other two phones stay connected to 3G all day. Both have stock ROMs. 1 is on stock Eclair (JI6) and the other has the stock Kies upgrade to Froyo. (Actually, during the first attempt to upgrade, Kies softbricked that phone, so I ODIN'ed it back to the JFD image I downloaded from XDA, and then successfully upgraded to stock KA6).
These other phones are my family's. My phone however, seems to be bumped down to EDGE as soon as I use it. In other words, if the phone is just sitting there charging, it indicates it is on the HSPDA network. If I pick it up and start using it, it bumps down to EDGE within a minute. I tried to hold it with my fingertips to avoid the "grip of death" but this does not help. (BTW, I can grip the other phones all day and they stay on 3G. So my fat hands do not seem to be the problem).
My phone has seen just a few ROMS: Bionix, Flagship and now running Trigger 2.5.
I have tried the following modems: JK6, JL5, KA6, KA7, and of course Trigger 2.5 comes with KB1.
I have also done the hardware contact fix (i.e. lift up the copper tabs).
After flashing in different modems and doing the hardware fix, I continue to experience the exact same phenomena.
I am at my wit's end. I DO NOT know what else to try to get the dang thing to stay on 3G or HSPDA. I know I should try going back to stock to see if that helps ... but I am pretty reluctant to go there.
Any ideas or suggestions would be much appreciated.
Well, not sure if it is where you are at, In places in Hawaii and Very Northern California I only get edge.....But so the sake of argument we will assume the signal is not the issue
Here is a way to do some testing :
I use this when i want to get 850wcdma (ATT 3g) it does work for that
Dial: *#*#197328640#*#*
Click [1] debug screen
Click [8] phone control
Click [7] network control
Click [2] band selection
This is where you make a change, default setting is [1] automatic,
Which means it chooses automatically between gsm/cdma (Edge vs 3g).
So we are going to change this and set it to wcdma band which is 3g.
Click [2] wcdma band
Click [1] wcdma all []
Now it should display “select wcdma all bands [*]"
Now on the bottom of your phone, click the menu key, it’s the one next to the home key, now click back, menu again one more time, back one more time, this is just to confirm it set to number 2 wcdma band.
Now click menu key one last time, click end.. and you are done. Now to double verify that the phone is locked into 3g, dial in: *#*#4636#*#*
Then click phone information Then scroll down to “set preferred network type” It should now have listed “wcdma only.” PS, if you tried to do a shortcut, and just set wcdma this way first without doing the lock above, it would just go back to gsm/cdma auto once you exit the screen.
Your phone should now be locked into 3g.
That may help good luck..........
oka1,
Thank you very much for your detailed reply. This sounded very promising. I followed every step of your instructions. The result was that I ended up with no network. The four bars area was replaced with an empty space. Attempts to access the web resulted in message that no network was available.
No biggie. Just went back through the process and set the phone back to the default. And I am now back the EDGE.
Any I too am in Northern California.
Thanks again.
Yeah Northern Cal north of Ukiah nothing but Edge, but then ATT and verizon are the same
Actually, SF Bay Area ... South Bay to be exact.
My prob is that I can get HSPDA ... as long as I leave the phone on my desk connected to the power cord. If I pick it up or move around the house, I lose connection to the 3G network and get downgraded to EDGE. This does NOT happen to the other two Vibrants that we have. They always get 3G.
This may be related to the Grip of Death. But only for my phone.
Well I am in Alameda and I have a similar problem. for what ever reason, If I am in my house the wireless WIFI makes my phone go to edge, go in my backyard, and I have 3g. Now since i am on the second floor, to only thing I can think is my wifi signal messes up my 3g cause in the front on my porch I get edge (13 ft above the street.........so I use wifi at home, but it still really bugs me that in the house I have edge and in the backyard I have 3g....... go figure
Hello,
I am coming from an Inspire 4g phone have been using the Not since its release date. I am having a similar issue with my Note that the Inspire had, but I am unable to work-around the issue the way the Inspire did.
My issue is that while my phone has great cell tower signal, my phone drops into Edge connectivity constantly. Prior to my Note upgrade, my Inspire would do the same thing, but I had a couple of work arounds I could do to lock back into 4G (HSPA+).
A) I could reboot the phone and the overwhelming majority of times it would go back to H+.
B) I could turn the mobile data radio off and then back on and again, the majority of the times, it would go back to H+.
C) The fix I used most often was to go into the phone dialer and dial *#*#4636#*#*. This brings up a back door to the testing screens and I could access the phone information section. In phone information, I could change the preferred network type and I would change from the default WCDMA preferred to either GSM ONLY or WCDMA ONLY depending on the area I was in. This not only work with near 100% success, it also locked the signal into H+ for longer periods of time.
Now that I have my Note, I have the same issue with the phone dropping to Edge service. However, when I try each of the 3 methods above, including *#*#4636#*#*, my phone stays locked into Edge. I can not get it to change.
I called AT&T about the issue and they explained to me that the phone will lock into the stronger signal, so if Edge is stronger, that is what I will get. I told them about my workaround with my Inspire and they could not give an explanation why it worked with that phone. I did talk them into re-sending the network information to my phone while on the call. They sent the information and while I was sitting still with full bars of signal strength, the phone miraculously popped into 4G service. I asked why it would change from Edge to H+ when they sent the network information since I didn't move to affect the signal and they could give me no explanation.
Does anyone have an idea how to make the Note ignore Edge service if H+ is available? If I can't figure this out, the Note is going back and I will stay with my Inspire 4G for now.
Thanks,
Roger
Flash the Rogers modem(I think)..its got RAT access or whatever its called.
Sent from my SAMSUNG-SGH-I727 using xda premium
(I don't have a Note yet but...) Settings- Wireless and Network- Mobile Network- Network Preferences. Maybe you can force it there. Keep in mind this is an LTE phone, and SIM, so a little different than our Inspires.
kimtyson said:
Settings- Wireless and Network- Mobile Network- Network Preferences.
Click to expand...
Click to collapse
Unavailable on the stock rom.
kimtyson said:
(I don't have a Note yet but...) Settings- Wireless and Network- Mobile Network- Network Preferences. Maybe you can force it there. Keep in mind this is an LTE phone, and SIM, so a little different than our Inspires.
Click to expand...
Click to collapse
As stated, this is not available in stock rom nor TPC Note 2, which I am currently running. However, based on what I remember seeing on other Samsung phones, the *#*#4636#*#* feature I reference is supposed to do the same thing.
Thanks for the replies. Looks like the RAT feature is locked. Using the Rogers Radio seems to fix the problem, but breaks video playback at this time.
I found it an other thread, so I don't take any credit for it as someone else posted it, but I have confirmed it works on my Galaxy Note
*#*#197328640#*#* > debug screen > phone control > network control > band selection
You need to do this after each reboot though as it does not stick.
To work around this I have made a contact and only left out the last * in it, so all you do is use that as a speed dial and you are good to go
Strating a new topic to figure out which radio works better on T-Mobile for AT&T JB update.
Before JB update, like several other people on this forum, I have been using i717 on T-Mobile network . 4G has been working fine with GT-N7005-IMM76D-DXLJ2 Rom and UVLG3modemfori717_gt-n7005amss radio.
1. UVLG3 modem with GT7005 amss gives no signal.
2. UVLG3 modem with JB amss gives no signal.
3. Stock radio and amss in JB update only connects to Edge. (unless you are in area where T-Mobile has 3g on 1900?)
4. Blaze ICS modem connects to 4g but signal bars are not shown in status bar.
For the best modem so far, check the below post...
http://forum.xda-developers.com/showthread.php?p=41052527
If anybody else tried any other combinations, please post your experience in this thread.
Thanks.
same here plus i try it with Telus modems too not signal (signal comes and gone)
I made my own combo for WIND in Canada (confirmed to work on T-Mobile with much higher speeds). It's really slow (about 1 Mbps down and 50 kbps up) but at least it works (good voice/signal strength and somewhat usable data)
It's the SGH-T989D (Telus Galaxy S II X) latest modem (TLMC4) and AMSS from the old Blaze modem posted around this forum. Just flash it with CWM.
http://speedy.sh/uyHBp/SGH-T989D-TLMC4-amss-from-blaze.zip
Steps:
1. Flash in CWM
2. On reboot, do a network scan
3. Open dialer, dial *#2263# and select WCDMA Prefs -> WCDMA 1700
4. Do network scan again, WIND (or whatever your AWS provider is) should appear. Select it and it should register.
5. You can multi task back to the service mode and go back and select "[1] Automatic" to use all bands again.
No responsibility if it bricks your phone, it works on my SGH-i717R without issues
OT: I also tried SGH-T989D_TLMC4_radio.zip and it works on Bell/Telus/Rogers without any mods. However, trying any T989 combos never really worked (some did, but data kept dropping).
windroidHD said:
Strating a new topic to figure out which radio works better on T-Mobile for AT&T JB update.
Before JB update, like several other people on this forum, I have been using i717 on T-Mobile network . 4G has been working fine with GT-N7005-IMM76D-DXLJ2 Rom and UVLG3modemfori717_gt-n7005amss radio.
1. UVLG3 modem with GT7005 amss gives no signal.
2. UVLG3 modem with JB amss gives no signal.
3. Stock radio and amss in JB update only connects to Edge. (unless you are in area where T-Mobile has 4g on 1900?)
4. Blaze ICS mpdem connects to 4g but signal bars are not shown in status bar.
If anybody else tried any other combinations, please post your experience in this thread.
Thanks.
Sent from here.
Click to expand...
Click to collapse
This is an important thread for this forum. I'm in the same situation, utilizing the AT&T rom on an AT&T device, and trying to use it on T-Mobile.
My experience has been strange. I am using the stock firmware radio with the AT&T JB update, and I seem to connect to 4G randomly on T-Mobile, switching between UMTS:3 and HSPAP15. I am usually on Edge more often than "4G". I don't have LTE in my area, and "3G" on 1900 doesn't work on my Wife's Iphone.
I tried the UVLG3 Modem for i717, and got no signal at all.
I haven't tried the Blaze modem. What I want to know, is what is the experience with Blaze when you look at system status? UMTS:3? HSPAP?
I am on stock modem in JB rom right now, shows UMTS3 in status.
Nothing strange about that, it is in UMTS when data is idle, anything else is when data is active.
You only get 3G on T-Mobile if its a "re-farmed" 1900 MHz region, where they moved 3G from AWS to 1900 MHz. If you go outside your zone you will only have 2G.
zivan56 said:
Nothing strange about that, it is in UMTS when data is idle, anything else is when data is active.
You only get 3G on T-Mobile if its a "re-farmed" 1900 MHz region, where they moved 3G from AWS to 1900 MHz. If you go outside your zone you will only have 2G.
Click to expand...
Click to collapse
What is HSPAP:15 considered? HSPA 15Mbps? Is that at 1700MHz or 1900Mhz?
crazeco said:
What is HSPAP:15 considered? HSPA 15Mbps? Is that at 1700MHz or 1900Mhz?
Click to expand...
Click to collapse
You would have to go to field test mode to find out, Android does not have such details. Dial *#0011# and find at the very top "RRC: .. BandX," where X is a number. Is it 4 (AWS) or 2 (1900Mhz)?
There may be an item (radio dependant) called DC_HSPA to indicate whether its dual cell HSPA(+). Post a screenshot and I can check it for you.
zivan56 said:
I made my own combo for WIND in Canada. It's really slow (about 1 Mbps down and 50 kbps up) but at least it works (good voice/signal strength and somewhat usable data)
It's the Blaze 4G latest modem (T769-UVMB1) and AMSS from the old Blaze modem posted around this forum. Just flash it with CWM.
http://www.speedyshare.com/YTNEb/T769-UVMB1-amss-from-blaze.zip
Steps:
1. Flash in CWM
2. On reboot, do a network scan
3. Open dialer, dial *#2263# and select WCDMA Prefs -> WCDMA 1700
4. Do network scan again, WIND (or whatever your AWS provider is) should appear. Select it and it should register.
5. You can multi task back to the service mode and go back and select
No responsibility if it bricks your phone, it works on my SGH-i717R without issues
OT: I also tried SGH-T989D_TLMC4_radio.zip and it works on Bell/Telus/Rogers without any mods. However, trying any T989 combos never really worked (some did, but data kept dropping).
Click to expand...
Click to collapse
With the T989D_TLMC4_radio i got the most sickiest DL ever on CM 10.1 but cant make calls only data and text did you think can modify to work on TMO.
BTW right now o using Telus TELL4 modem and work amazing
Sent from my SAMSUNG-SGH-I717 using Tapatalk 2
Mervingio said:
With the T989D_TLMC4_radio i got the most sickiest DL ever on CM 10.1 but cant make calls only data and text did you think can modify to work on TMO.
BTW right now o using Telus TELL4 modem and work amazing
Sent from my SAMSUNG-SGH-I717 using Tapatalk 2
Click to expand...
Click to collapse
Hmm, can you try this. I've tested it a bit on WIND and data/voice works...the data is slighly more stable/faster (still around 1.5 Mbps/50 Kbps for me)
http://speedy.sh/uyHBp/SGH-T989D-TLMC4-amss-from-blaze.zip
IT works for me on WIND, so it should work on T-Mobile. Same steps as in my previous post above to get it to see AWS carriers. If your T-Mobile service is 1900 MHz, it may just work without any of those steps.
Btw, for some reason it only sees WIND (the modem is non WIND specific) and no other AWS carriers (i.e Mobilicity) when set to WCDMA 1700. No idea why.
I
zivan56 said:
Hmm, can you try this. I've tested it a bit on WIND and data/voice works...the data is slighly more stable/faster (still around 1.5 Mbps/50 Kbps for me)
http://speedy.sh/uyHBp/SGH-T989D-TLMC4-amss-from-blaze.zip
IT works for me on WIND, so it should work on T-Mobile. Same steps as in my previous post above to get it to see AWS carriers. If your T-Mobile service is 1900 MHz, it may just work without any of those steps.
Btw, for some reason it only sees WIND (the modem is non WIND specific) and no other AWS carriers (i.e Mobilicity) when set to WCDMA 1700. No idea why.
Click to expand...
Click to collapse
Tried it, signal strength went from 2 bars with stock modem to 4 bars, status shows UMTS3 when idle and switches to HSPAP:15 briefly.
Speed test
outside the house 7000kbps/1000kbps
Inside the house 1650kbps/66kbps
*#0011# shows rrc band 4, previously it was band 2.
*#2263# doesn't shows any item with * infront, previously automatic had * infront of it.
Tried setting wcdma to 1700 and saw the same performance, rrc band4 and switching between umts3 and hspap:15.
Havn't tested call quality but this has been the best modem so far.
Thanks for sharing.
zivan56 said:
Hmm, can you try this. I've tested it a bit on WIND and data/voice works...the data is slighly more stable/faster (still around 1.5 Mbps/50 Kbps for me)
http://speedy.sh/uyHBp/SGH-T989D-TLMC4-amss-from-blaze.zip
IT works for me on WIND, so it should work on T-Mobile. Same steps as in my previous post above to get it to see AWS carriers. If your T-Mobile service is 1900 MHz, it may just work without any of those steps.
Btw, for some reason it only sees WIND (the modem is non WIND specific) and no other AWS carriers (i.e Mobilicity) when set to WCDMA 1700. No idea why.
Click to expand...
Click to collapse
not sure why but with this ROM (jelly bean) i can lock DC-HSPA8+ and damn it go fast!!!!
this pics are with your modem i will test later today when i go to the mall now works perfect!
Thanks for the help
zivan56 said:
You would have to go to field test mode to find out, Android does not have such details. Dial *#0011# and find at the very top "RRC: .. BandX," where X is a number. Is it 4 (AWS) or 2 (1900Mhz)?
There may be an item (radio dependant) called DC_HSPA to indicate whether its dual cell HSPA(+). Post a screenshot and I can check it for you.
Click to expand...
Click to collapse
I'm now using the Blaze radios posted by Zivan in the link above. I'm getting Band 4 CPCH and FCPH and DCH. Averaging around 3-6Mbps down and 300Kbps up.
crazeco said:
I'm now using the Blaze radios posted by Zivan in the link above. I'm getting Band 4 CPCH and FCPH and DCH. Averaging around 3-6Mbps down and 300Kbps up.
Click to expand...
Click to collapse
Great!!
Mervingio said:
Great!!
Click to expand...
Click to collapse
To be honest, I'm getting better T-Mobile 4g reception with that modified Blaze radio on JB than I did on ICS with UVLG3. Not going to complain!
Anybody managed to get LTE with a JB rom yet?
Question ?.........I picked wcdma 1700 and I'm getting crazy good speeds ....9down 2up..sometimes better What is safe cpu temps? Cause I think it may be heating up
Sent from my SAMSUNG-SGH-I717 using xda app-developers app
Sent from my SAMSUNG-SGH-I717 using xda app-developers app
Wow, good to hear folks...I'm getting rather terrible speeds on WIND. But the phone works, I did a bunch of calling/texting/data usage and its been stable for over a day.
Well I had to reflash for some reason it was picking up excellent speeds then poof gone .. tried changing back to 1900... nothing .. so I reflashed and just picked automatic
Sent from my SAMSUNG-SGH-I717 using xda app-developers app
I was out of town this past weekend. Wisconsin Dells if anyone is interested. While I was there I was experiencing some bad signal, so I read multiple times that you could force a PRL update for your phone to allow it to possibly roam on newer towers. I dialed the *228, then pressed 2. After the update my phone will now only connect to 3g. Even back home now, which I know for sure is a 4g area, I am still stuck on 3g. I spent quite a while messing with settings. The one that controls what network to use. I tried them all really. But its set to LTE/CDMA only right now.
I was running CM10.1 from 8/3. So I formatted system/data/cache/dalvik, everything basically, reflashed the latest build of CM 10.1, and it is still doing it.
Any other ideas before I reflash back to stock and call Verizon?
So I flashed back to stock. Still stuck in 3g. But in the touchwiz interface now it's a bit odd. In Mobile Networks, the list item says Preferred network mode: CDMA/LTE/EVDO. When I touch it, it presents 3 options, Global, LTE / CDMA, and GSM / UMTS. The LTE / CDMA item is selected. The odd part is that even though LTE is listed first on the option when it is selected from the pop up menu, it still says CDMA is first in the preferred network mode, the gray text. That is even more odd is that if I select the GSM one, it doesn't connect to anything, which is expected. But then if I go back into the option and select LTE / CDMA, the status bar icon will say 4g for a half second and then say 3g.
Any ideas?
I found this. Is my sim card really toasted?
https://community.verizonwireless.com/thread/786562
"I was recently browsing a different message board to see what was being said about the GS3's poor reception and data, and I came across a discussion on "updating towers" using *228. From what I read, it seems that dialing this number from a 4G phone not only does nothing to update your towers, but it also destroys your SIM card, and prevents you from accessing 4g. Consequently, you will need to get a replacement SIM card. I find it hard to believe that Verizon would allow something like this to happen. It seems that they would notify their customers when upgrading.
Has this happened to anyone???"
Update: I called Verizon. They confirmed the sim can get toasted if you dial *228 on a 4g phone. So I'll have to go into the store tomorrow morning to get a new sim. The support guy was cool about it. It said he did this exact same thing himself before he started working for Verizon.
Yeah I have heard that dialing *228 from a 4G phone is a big no-no but I didnt know that it actually fries your sim. At least you can get another one for free.
Sent from my SCH-I545 using Tapatalk 4
This could be a handy sticky. Just in case more people try/do this.
Send from my Nexus 4
I wish I had seen this thread sooner and I have been spending days trying to figure out why my phone would no longer connect to the LTE network after traveling to a 3G only area. Whoops!
I definitely think this should be a sticky - or at least warning not to use *228.
Hi. I just got the Z2 last week and I need some help with my LTE set up.
1. I am using my nano Sim from my HTC One M8.
2. I downloaded the att file for internet settings
3. Network Mode - LTE (Preferred)
3. The icon reads LTE
Looks like everything is working, but when I run a speed test I get terrible results. Like 0.5 mbps bad.
I have tested in various locations,but always get bad results.
Any ideas?
Thanks!
Green1534 said:
Hi. I just got the Z2 last week and I need some help with my LTE set up.
1. I am using my nano Sim from my HTC One M8.
2. I downloaded the att file for internet settings
3. Network Mode - LTE (Preferred)
3. The icon reads LTE
Looks like everything is working, but when I run a speed test I get terrible results. Like 0.5 mbps bad.
I have tested in various locations,but always get bad results.
Any ideas?
Thanks!
Click to expand...
Click to collapse
LTE isn't all it's cracked up to be .. I got an LTE sim to try recently in a large city. It turned out that H+ was actually faster , LTE was 1-2Mb, H+ was 7-8Mb , however in a less populated area I got LTE upto 20Mb. It's still down to the network in the end.
Thanks for the reply defsix. I tested on h+ also. Same results at 0.5 Mbps.
I know it comes down to coverage, but LTE is good in my area. I tested my wife's iPhone and got about 5 mbps at the same time I got 0.5.
That's why I'm not sure if I don't have something set up right.
So if I am getting the LTE icon is it just bad luck?
Green1534 said:
Thanks for the reply defsix. I tested on h+ also. Same results at 0.5 Mbps.
I know it comes down to coverage, but LTE is good in my area. I tested my wife's iPhone and got about 5 mbps at the same time I got 0.5.
That's why I'm not sure if I don't have something set up right.
So if I am getting the LTE icon is it just bad luck?
Click to expand...
Click to collapse
I'm assuming you have the correct settings on your phone ? Network settings etc.
Did you call AT&T to register the IMEI of the phone to provision it?
I've heard from several folks on att that you have to call them to set it up.
Drop by an AT&T store to see if you can get a new SIM card. Yours maybe outdated such that the newer one which could have newer information to support other towers.
I'm actually to change my SIM card up because one area I usually go to is a bit weak and they did look at my SIM card info and told me mine was an older one and try getting a new one.
If you did all the updates on the phone it shouldn't even show LTE but 4G instead. From my understanding one of the updates broke the LTE symbol so it doesnt show anymore. Mine never says it and I live in an LTE Att area.