Develop Bugs

[Q] Samsung S3. No LTE after reboot

It is my first forum post and I believe I am posting it in the right section... I tried finding a similar problem to mine, but seemed to only find people that wanted to turn LTE off instead of on. The AT&T Galaxy S3 phone is rooted and I have gone between ics and jb roms and have gotten LTE to work every time. The problem is after I reboot the phone I lose LTE. I get 20+ up 10 down on LTE. After I loose LTE I get around 8 up 4 down.
I have tried.
1.) Re-installing a rom which gives me LTE until I reboot phone.
2.) I have tried installing modems from http://forum.xda-developers.com/showthread.php?t=1831898. If I have lost LTE after reboot, I can (9 out of 10) get LTE to work again after installing a modem. I lose it once I reboot the phone again though and am unable to flash a new modem to get LTE back to working and it won't unless I do 1.) again.
3.) I have made sure apn settings are on the correct pta lte setting. Usually most of the rom's have that already set to begin with.
4.) I have tried the *#2263# to change it to LTE. This WORKS and will reboot my phone into LTE everytime, but I lose being able to make phone calls, etc. From what I understand as well, I am unable to go to 3g/2g after settings LTE ALL and I don't want that either...
It is the only problem I have had with this phone. I notice a lot of times after I install a rom and reboot, it upgrades, and I lose LTE. I install a modem and get LTE back. I reboot phone normally without doing anything to the phone and it upgrades apps again and I lose LTE. That is the only conclusion I can come to as to why I lose LTE after reboot.

terminalerror said:
It is my first forum post and I believe I am posting it in the right section... I tried finding a similar problem to mine, but seemed to only find people that wanted to turn LTE off instead of on. The AT&T Galaxy S3 phone is rooted and I have gone between ics and jb roms and have gotten LTE to work every time. The problem is after I reboot the phone I lose LTE. I get 20+ up 10 down on LTE. After I loose LTE I get around 8 up 4 down.
I have tried.
1.) Re-installing a rom which gives me LTE until I reboot phone.
2.) I have tried installing modems from http://forum.xda-developers.com/showthread.php?t=1831898. If I have lost LTE after reboot, I can (9 out of 10) get LTE to work again after installing a modem. I lose it once I reboot the phone again though and am unable to flash a new modem to get LTE back to working and it won't unless I do 1.) again.
3.) I have made sure apn settings are on the correct pta lte setting. Usually most of the rom's have that already set to begin with.
4.) I have tried the *#2263# to change it to LTE. This WORKS and will reboot my phone into LTE everytime, but I lose being able to make phone calls, etc. From what I understand as well, I am unable to go to 3g/2g after settings LTE ALL and I don't want that either...
It is the only problem I have had with this phone. I notice a lot of times after I install a rom and reboot, it upgrades, and I lose LTE. I install a modem and get LTE back. I reboot phone normally without doing anything to the phone and it upgrades apps again and I lose LTE. That is the only conclusion I can come to as to why I lose LTE after reboot.
Click to expand...
Click to collapse
I am in the same boat as you. I can force LTE with *#*#4636#*#* and setting it to LTe only. But I lose phone calls and if I restart it goes back to WCDMA.

What rom are you using some roms don't have the late icon they have 4g instead. Also double check that you have the right lte apn enabled
Sent from my SGH-I747M using xda app-developers app

offwiththeface said:
What rom are you using some roms don't have the late icon they have 4g instead. Also double check that you have the right lte apn enabled
Sent from my SGH-I747M using xda app-developers app
Click to expand...
Click to collapse
Yea I realized that jb roms do not show 4g lte, they just show 4g. I check to see if I have LTE by doing going to the Settings->About Device-> Status and looking at Mobile network type... and/or a speed test as well.
I came from and tried these rom's
Year of The Dragon
Ariel.2.07 [2ETO][Aroma]
WanamLite Smooth,Stable & Battery
Right now I am on Stock TouchWiz Jelly Bean PORT (JellyBean 747 Milestone 3)
I have gotten LTE speeds on every single one of the roms until I reboot phone.

[Update- Best Solution So far]
I found that using the WanamLite Rom http://forum.xda-developers.com/showthread.php?t=1782732 enabled me to get LTE back fairly easy.
Everything is in the Settings->More Settings->Mobile Networks area.
1. I entered in a new Access point and just put Name: "pta" APN: "pta". You can fill out the rest like the MMSC, MMS proxy, etc but I did not need to.
2. Then went to Network Operators and waited for it to search for the networks (takes a minute or two). It showed up for me as two options being Maritime and AT&T. I selected Maritime and registered it. I was not able to register on AT&T and I don't even know what Maritime is. However,
3. I went to Network mode: Set it to GSM/HSPA/LTE(Auto mode). I get LTE every time.
Every time I reboot I can get LTE to work by doing steps 2.) and 3.) and is a little annoying, but better than having to flash a rom every time I reboot and lose LTE. I would like to try and find a solution though where I wouldn't have to do this every time I reboot.
[EDIT] There might be roaming charges, but by disabling Data roaming you should be fine. I believe you might incur charges if you try connecting to this network while on a cruise and have data roaming enabled. I have not done a lot of research on this so I could be wrong.

[Q] D851 (T Mobile) on AT&T - Network Data Keeps Dropping

I just bought a T Mobile LG G3 (D851) for use on AT&T. The guy I bought it from got the unlock code from T Mobile and that is all squared away and unlocked. Things are basically working on AT&T, but data is not working reliably for me. It works fine for awhile, then it just stops working--the 4G/LTE logo in the status bar disappears and I have no connectivity. I can still make phone calls and send/receive SMS texts (though no MMS texts), and if a wifi network is around, that works too. Rebooting does not seem to correct it (though it does start working again eventually).
I don't know if it is just random, but it does seem to happen after I'm leaving somewhere with wifi (and that may not even be relevant--might be that's just when I notice it).
I have verified my APN settings (as well as tried other slightly different settings I've found around the web), but the data network still drops out. Yesterday, I discovered a technique that seems to reliably bring it back on after it has dropped out. If I change the Network Mode to anything else (ex: just GSM), then back out of the network options menu... then go back in and set Network Mode back to LTE (etc). Every time I have tried this, I get the 4G/LTE logo back in the status bar and my connectivity is back.
I know there is some difference in the LTE bands supported by AT&T and the T Mobile LG G3 (D851), but the phone supports band 17, which I'm told is the main LTE band used by AT&T. At this point, I think I'd be satisfied just to have consistent 4G (non-LTE) data.
Any idea what might be the issue? Or anything I can try out? I'm considering flashing a different rom to see if that helps, but wanted to exhaust other options first.
Thanks...

G4 H815 doesn't stick to LTE - apn okay, lp&mm stock kdz already flashed

Hello!
I have a big problem with my G4 (H815 version, Germany) beginning with the switch from CM13 to the (stock based) Genisys 3.2 ROM. I've tried to fix it for three days now but without success. It doesn't stick to LTE anymore like it should do and did before. After a reboot it does sometimes connect to LTE but after switching back from wifi or airplane mode it's showing the "no signal" icon. Then it takes some seconds until it reconnects to the mobile network but now just to 2G or 3G. From this point it's not willing to reconnect to LTE, even not through the manual RAT-selection. "Force LTE" using the hidden menu then results in no network connection. However, after restoring my EFS-partition-backup with TWRP (from a time when it was working perfectly) it's connecting to LTE directly after boot but only once and only until you toggle wifi or go offline - like described before. After the next reboot it will mostly connect to 3G and then maybe switch to LTE sometimes or not.
Of course I have checked, deleted and restored my APN multiple times, I have also recovered to a stock V20b and V10d .kdz using LG UP in refurbish mode. Unfortunately even on the fresh and untouched V10d install it shows the same strange behaviour. Restoring the CM13 backup (including EFS partition), which has worked perfectly before, shows the same network bug now.
My sim-card is still working perfectly in my other phones. It still connects and reconnects almost instantly to LTE in my old S4 in places where the G4 did the same but struggles now.
I have even tried the cdmatool which is used to unlock additional LTE bands. I didn't change anything but it does show all usual LTE-bands which are needed for my provider.
Does anyone have an idea what I could try next? I'm living in an area with much better LTE than 3G connection and paying for a quite expensive LTE contract so a working LTE is very important for me. If I don't get that to work again I would need to replace my just over one month old G4 :crying:
Many thanks in advance for your answers
f-rouz

Meanwhile I have also tried another simcard. Still no LTE

i have the exact same problem, well, almost. no unlocked bootloader, but when i first got the phone i root injected the system.img and flashed away, thought everything was fine. now it just doesn't reconnect to 4G. well, at home at least. on my S4 i get 4 out of 5 bars on 4G, with the G4 i get 2 or 3 bars out of 5 on 4G, so the signal isn't great but good enough. i live in hastings (a town) and went to brighton today (a city) where the signal is max 4G, and the device does pick it up. but as soon as i go through a 3G area to home, it doesn't reconnect. have tried flashing original system.img back, upgrading to MM 6.0 after factory reset (via LG bridge), then downgraded again to V10c via LGUP - factory reset before the downgrade, no joy, still the same.
when you say you have forced LTE in hidden menu, did you try this - enter 277634#*# in dialer and go to field test > modem settings > lte band selection and select the band for your operator, which can be found on 'wiki europe lte bands'. there were two bands for my provider (three UK) and band 3 was what i wanted. i can now switch to 4G but it's a pain having to this every time i come home ( i use my phone for home internet via tethering).
worst part is, having refrained from unlocking the bootloader to save the warranty, i phoned LG today to send it back as faulty and explained i could switch it to lte band 3 via the hidden menu and they told me my warranty was now invalid as had OPENED the hidden menu (they told me this after taking my imei). so if anyone reads this and phones LG for a repair, don't tell them you have accessed the hidden menu if you have done what i did.
think i'm just gonna sell the phone, make a palpable loss and buy another one, as i love the phone

Wow, I haven't thought that from LG. I feel like I've searched the whole internet already and nobody has a solution to this problem. I'm about to send my G4 back to Amazon (or sell it otherwise), hope the best and get myself a Oneplus Two because the G4 seems to be too *****y from the development standpoint. I've never had a situation like this with my previous Samsung phones since 2009. I will miss this camera though. And the NFC and the wireless and fast charging capability... the G4 is a nice phone nevertheless...
Edit: And yes, I have tried the "277634#*#" hidden menu, although it isn't accessible through this code on MM any more (you need a terminal command to start this).

Have you tried limiting it to 4G/2G in hidden menu? Mine also have a similar problem in Lollipop in that it is very aggressive in dropping to 3G. That worked for me. Phone doesn't drop to 2G much provided you have decent LTE coverage.
Now I'm on Marshmallow and not rooted, thus cannot do the same. Though it seems to be sticking to LTE a bit better than before.

I have tried that but it doesn't work. As I don't get any network connection wenn forcing LTE only, forcing LTE/2g results in 2g only.

My G4 still doesn't want to connect to LTE so I have ordered a S6 now... As I still have no idea what was causing this I just can't risk that happening again. It has been a short journey for my first LG and me and I really liked my G4 actually... Bye G4 community

you just needed to flash the stock modem, most likely

Unfortunately, it isn't that easy. That was of course the first thing I did (and not just one time)...

[GUIDE] [HOW TO] Fix VS986 dropping down to 3G/H+ from 4G LTE

I've been working on a fix since a long time now. If you are in SD community then you prolly know me. Anyway I was able to fix this on two of my phones and it's working fine. I tested for 12 hours now. I'll also tell you in the end what problems I'm seeing. I'm also working on a fix for that.
I noticed that a service is started when the fallback happens but if I kill that service the network also dies. But if you follow the below method it safely starts a new service which kills the one that's responsible for killing the 4G/LTE
1. Upgrade your phone to 13B firmware
2. Root 13B
3. Now download Shortcut Master lite app from play store.
4. Now add these shortcuts to your favorites in the "Shortcut Master lite app". You can search for "LTE" and click on search button
LTEBandSelection
LTETestMain
LTE System Selection
CDMAPreference
5. Now click on "LTEBandSelection" and enable all the bands
6. Save and reboot
7. You now need to enable your data and turn off your wifi. Make sure your phone is in Global mode (in settings >> Mobile networks >> System select)
8. After your phone is rebooted open "Shortcut Master lite" app.
9. Now tap on LTETestMain
10. Select Click on CDMA preference.
Now choose Band preference and select "any"
P_REV_Preference ---> "MOB_P_REV 3
This is important.. EVDO Revision --> Rev A
11. "LTE Connect w/o IMS PDN" must be checked
12. Now go back to your main menu in shortcut master lit app
13. This step is very important. Changing the timeout is important. Tap on LTE System Selection
Except "Scan duration" add a couple zeros to all the other timers. For eg: T_mpsr timer (Min) is 200
The fallback timer will reset itself after reboot. But don't worry the configuration is already updated with the new value. For some reasons the shortcut master lite app is not picking it up.
14. Now finally click on "CDMA preference" in the main menu and make sure it has the value you set in Step 10
At step 10 or 13 your network should go away and your phone should complain about "no network". That's fine. just ignore the message.
Now finally reboot your phone. That's it. You should now have 4G LTE and it won't fallback to 3G or H+
The only problem is when I'm on a call my 4G LTE is dropped to 3G/H+. But after I hang up it goes back to 4G LTE after 12 seconds. I don't know if it's an expected behavior. But I'm trying to see if there is a fix for that.
I tested this with Tmobile. Make sure your APN settings are correct.

Not working for me on Cricket (AT&T). Still will always go back to H+, 4G LTE only works when I select CDMA.

konradsa said:
Not working for me on Cricket (AT&T). Still will always go back to H+, 4G LTE only works when I select CDMA.
Click to expand...
Click to collapse
I tried it on my two phones (Both tmobile). My friend just tried it on his phone. It worked for him too.

motorhead_biker said:
I tried it on my two phones (Both tmobile). My friend just tried it on his phone. It worked for him too.
Click to expand...
Click to collapse
That's great! I hope we can figure out also what we need to do to get it to work for AT&T, I am sure it's probably just some small tweaks required.

konradsa said:
That's great! I hope we can figure out also what we need to do to get it to work for AT&T, I am sure it's probably just some small tweaks required.
Click to expand...
Click to collapse
I will try it with my roomies att sim tonight. He has a nano sim, I need to find a sim adapter.

Awesome, thank you! worked for me T-mobile.
it initially didn't work but I had to turn data off then on.
It also cycles me to 2g speed for a few seconds sometimes but that may be due to poor signal in building.

pwtzz said:
Awesome, thank you! worked for me T-mobile.
it initially didn't work but I had to turn data off then on.
It also cycles me to 2g speed for a few seconds sometimes but that may be due to poor signal in building.
Click to expand...
Click to collapse
Yeah It's due to the poor signal. I got that too. You can check your signal strength using LTE discover app.
But overall it's working fine for Tmobile. I'm gonna try and fix ATT tonight.

Is 13B the main thing in the solution? I've changed these settings before on 11A and wasn't fixed. I tried these numbers on 11A and still don't work.
Also, unless a phone supports VOLTE, it'll fall back to 3G/H for calls.

eigen said:
Is 13B the main thing in the solution? I've changed these settings before on 11A and wasn't fixed. I tried these numbers on 11A and still don't work.
Also, unless a phone supports VOLTE, it'll fall back to 3G/H for calls.
Click to expand...
Click to collapse
I tried in 11A and it didn't work for me. So I guess it needs 13B.

So I tried various combinations last night for AT&T/Cricket, but I was not able to get it to work. No matter what I tried, when I had 4G LTE, voice wouldn't work and whenever voice worked, I was back to H+.
If others are reporting that T-Mobile works reliably on 4G and nobody can figure out how to make this work for AT&T, I guess it's time to switch to T-Mobile.

konradsa said:
So I tried various combinations last night for AT&T/Cricket, but I was not able to get it to work. No matter what I tried, when I had 4G LTE, voice wouldn't work and whenever voice worked, I was back to H+.
If others are reporting that T-Mobile works reliably on 4G and nobody can figure out how to make this work for AT&T, I guess it's time to switch to T-Mobile.
Click to expand...
Click to collapse
No. Hold on. I have a solution for ATT too. I tried something last night. Actually while I was working on a solution for ATT I found that we don't even have to go through the steps I mentioned in my OP to solve the problem. It boils down to invoking a service and killing a native VZW service.
The ATT solution I have works but in low signal area 4G fades and it doesn't fallback to 3G or H+. I had to recycle data to get 3G or H+.

It's Working!!!!!!!!! Thank you!!!!!!!
You just made my life much better now!
I finally have a phone which is great and also finally have good reception!
I Love U!

motorhead_biker said:
No. Hold on. I have a solution for ATT too. I tried something last night. Actually while I was working on a solution for ATT I found that we don't even have to go through the steps I mentioned in my OP to solve the problem. It boils down to invoking a service and killing a native VZW service.
The ATT solution I have works but in low signal area 4G fades and it doesn't fallback to 3G or H+. I had to recycle data to get 3G or H+.
Click to expand...
Click to collapse
Yes, that same thing happens when you switch to CDMA mode with AT&T. Voice doesn't work then (obviously), but it also doesn't fall back to H+ automatically, when you lose 4G coverage you pretty much lose signal all together.

konradsa said:
Yes, that same thing happens when you switch to CDMA mode with AT&T. Voice doesn't work then (obviously), but it also doesn't fall back to H+ automatically, when you lose 4G coverage you pretty much lose signal all together.
Click to expand...
Click to collapse
Yeah I know. I also know why that is happening. Actually I think it's a bug in the baseband firmware. But we can fix that issue by just overriding the command that was sent by baseband firmware.

ron.r said:
It's Working!!!!!!!!! Thank you!!!!!!!
You just made my life much better now!
I finally have a phone which is great and also finally have good reception!
I Love U!
Click to expand...
Click to collapse
Lol.. rep me in SD :laugh:

konradsa said:
Yes, that same thing happens when you switch to CDMA mode with AT&T. Voice doesn't work then (obviously), but it also doesn't fall back to H+ automatically, when you lose 4G coverage you pretty much lose signal all together.
Click to expand...
Click to collapse
Do you have a working fix for AT&T/Cricket? Is it different than the T-Mobile?

motorhead_biker said:
Lol.. rep me in SD :laugh:
Click to expand...
Click to collapse
Ha! You are repped!
What root did you use? and steps?
easyroot?
did you split the file and merge it back?

I must have really bad luck or something. It doesn't work for me. The Tbsr_cdma timer resets back to 2 at reboot.
Edit: Appears to be working. Nice job!

renoob said:
Ha! You are repped!
What root did you use? and steps?
easyroot?
did you split the file and merge it back?
Click to expand...
Click to collapse
Root? I just flashed the rooted sys image. That's it. instead of copying it in the FAT32 memory card just copy it to your phone's internal and you don't have to deal with split and merge stuff

If it drops out of 4G on a call then you're talking on 1X. So no video chat, no HD voice and no voice + data?

Question Unable to retain/regain signal without reboot/airplane mode toggle

I'm at my wit's end with this. I got this phone last year and it worked perfect until the stock Android 13 update. Then it wouldn't hold a signal to save its own life. I finally have wifi here so it's not as much of an issue, but when I leave my house I have to toggle airplane mode to get it to work again, or it's stuck on "emergency calling only" forever. I did recently put Lineage on it, thinking maybe that would help. The last couple updates it's a little better, it will sometimes get signal back on its own. However more often than not I have to toggle airplane mode or reboot to get service back. This happens all the time, a dozen or more times a day depending on how often I lose service. I did try to search the forums for an answer, but I kept getting errors back with the exception of one result with the same issue that said "tmobile only" under the fix.
I have:
Reset network settings
Reset APN
Manually selected a carrier and switched it back
Cleared cache through Android Settings
disabled/enabled mobile data
Toggled Mobile data always active
Any help would be greatly appreciated. Seriously considering going back to my LG G8 ThinQ and selling this thing, but I love the cameras on it. Side note: When I put the SIM in my old phone none of these problems exist.
Model: LE2125
Carrier: Verizon
Lineage ver.: 20230613

Caboose27 said:
I'm at my wit's end with this. I got this phone last year and it worked perfect until the stock Android 13 update. Then it wouldn't hold a signal to save its own life. I finally have wifi here so it's not as much of an issue, but when I leave my house I have to toggle airplane mode to get it to work again, or it's stuck on "emergency calling only" forever. I did recently put Lineage on it, thinking maybe that would help. The last couple updates it's a little better, it will sometimes get signal back on its own. However more often than not I have to toggle airplane mode or reboot to get service back. This happens all the time, a dozen or more times a day depending on how often I lose service. I did try to search the forums for an answer, but I kept getting errors back with the exception of one result with the same issue that said "tmobile only" under the fix.
I have:
Reset network settings
Reset APN
Manually selected a carrier and switched it back
Cleared cache through Android Settings
disabled/enabled mobile data
Toggled Mobile data always active
Any help would be greatly appreciated. Seriously considering going back to my LG G8 ThinQ and selling this thing, but I love the cameras on it. Side note: When I put the SIM in my old phone none of these problems exist.
Model: LE2125
Carrier: Verizon
Lineage ver.: 20230613
Click to expand...
Click to collapse
Maybe contact Verizon support. They should be able to fix it or at least tell you what the problem is.

TheGhost1951 said:
Maybe contact Verizon support. They should be able to fix it or at least tell you what the problem is.
Click to expand...
Click to collapse
I tried that. I couldn't get anyone that was a technician on the phone and eventually after three days of not getting an answer they closed the ticket.

Caboose27 said:
I tried that. I couldn't get anyone that was a technician on the phone and eventually after three days of not getting an answer they closed the ticket.
Click to expand...
Click to collapse
WOW, glad I am with TMO. Their support is the best I have ever worked with. To me they set the standard.

You said you reset the APN, but did you check to see if the APN is the same as on your other phone that doesn't have any issues with mobile service? Maybe check to see if they are the same, and if not put the APN in that works

Amazoniac said:
You said you reset the APN, but did you check to see if the APN is the same as on your other phone that doesn't have any issues with mobile service? Maybe check to see if they are the same, and if not put the APN in that works
Click to expand...
Click to collapse
That's a good idea, I'll do that tomorrow. Thaanks!

Assuming you're unlocked and rooted since running Lineage, so add this module in Magisk, and maybe also enable mobile data always active in developer settings for now as well.
[TMO] OOS/COS DATA FIX
TO CLARIFY THIS IS A ROOT ONLY FIX After gaining root install given module. Data is now retained. Even after reboot(s). No empty slot or waiting. Issue is TMO variant is showing multi sim. So props were added to make it like a conversion to...
forum.xda-developers.com

Caboose27 said:
I'm at my wit's end with this. I got this phone last year and it worked perfect until the stock Android 13 update. Then it wouldn't hold a signal to save its own life. I finally have wifi here so it's not as much of an issue, but when I leave my house I have to toggle airplane mode to get it to work again, or it's stuck on "emergency calling only" forever. I did recently put Lineage on it, thinking maybe that would help. The last couple updates it's a little better, it will sometimes get signal back on its own. However more often than not I have to toggle airplane mode or reboot to get service back. This happens all the time, a dozen or more times a day depending on how often I lose service. I did try to search the forums for an answer, but I kept getting errors back with the exception of one result with the same issue that said "tmobile only" under the fix.
I have:
Reset network settings
Reset APN
Manually selected a carrier and switched it back
Cleared cache through Android Settings
disabled/enabled mobile data
Toggled Mobile data always active
Any help would be greatly appreciated. Seriously considering going back to my LG G8 ThinQ and selling this thing, but I love the cameras on it. Side note: When I put the SIM in my old phone none of these problems exist.
Model: LE2125
Carrier: Verizon
Lineage ver.: 20230613
Click to expand...
Click to collapse
Exact same issue, unlocked LE2125, TMobile simcard. Didn't have issue on custom ROM, but this is happening on OOS13. Tried everything NSA SA 5g dev settings nothing worked. Living with trying to remember to toggle airplane mode periodically.
Try App "connection stabilizer booster" actually helps w root
Connection Stabilizer Booster - Apps on Google Play
Fix cell and wifi connectivity issues. Improve your mobile internet experience.
play.google.com

Life got in the way and I haven't had a chance to try this yet. Probably this coming weekend.