Develop Bugs

[HELP] My phone constantly switches to CDMA and than has no signal

Hello I bought my phone off of ebay it was already flashed with tasks rom when I got it and the only problem I have which is very annoying is that it constantly switches from LTE/GSM/CDMA to CDMA only when I goto settings>more>mobile networks...Whenever there is no signal it is set to CDMA only I'm not sure what the problem is but its very frustrurating when I cant make calls when I need to...Is this a known problem? Will I have to revert back to stock?

n023b said:
Hello I bought my phone off of ebay it was already flashed with tasks rom when I got it and the only problem I have which is very annoying is that it constantly switches from LTE/GSM/CDMA to CDMA only when I goto settings>more>mobile networks...Whenever there is no signal it is set to CDMA only I'm not sure what the problem is but its very frustrurating when I cant make calls when I need to...Is this a known problem? Will I have to revert back to stock?
Click to expand...
Click to collapse
who is your carrier and what APNs are installed? also, you're in a GSM forum

xBeerdroiDx said:
who is your carrier and what APNs are installed? also, you're in a GSM forum
Click to expand...
Click to collapse
My carrier is Fido (GSM) its the same as at&t in the US or Rogers in Canada
By APNs do you mean Access Point Names? If so there are three options
Fido Default
fido-core appl1.apn which is the one I use since I use LTE
Fido Internet
internet.fido.ca
Fido tethering
isp.fido.apn

n023b said:
My carrier is Fido (GSM) its the same as at&t in the US or Rogers in Canada
By APNs do you mean Access Point Names? If so there are three options
Fido Default
fido-core appl1.apn which is the one I use since I use LTE
Fido Internet
internet.fido.ca
Fido tethering
isp.fido.apn
Click to expand...
Click to collapse
Fido's website says to use LTEMOBILE.APN if you have an LTE device
http://www.fido.ca/web/content/phonewarranty/configure_unlocked_device_guide&lang=en

xBeerdroiDx said:
Fido's website says to use LTEMOBILE.APN if you have an LTE device
http://www.fido.ca/web/content/phonewarranty/configure_unlocked_device_guide&lang=en
Click to expand...
Click to collapse
Just checked although its named after the core one it has the LTE settings I've been using LTE fine

Even though the settings were the same I still made a new profile for LTE and its having the same problems Sometimes toggling airplane mode or restarting the phone seems to fix it
Again the problem is that the phone constantly loses signal and the mobile network setting says "CDMA only" if I change it back to LTE/GSM/CDMA sometimes the signal will come back

n023b said:
Even though the settings were the same I still made a new profile for LTE and its having the same problems Sometimes toggling airplane mode or restarting the phone seems to fix it
Again the problem is that the phone constantly loses signal and the mobile network setting says "CDMA only" if I change it back to LTE/GSM/CDMA sometimes the signal will come back
Click to expand...
Click to collapse
the fact that your gsm device has built in options for cdma and consistently tries switching to cdma (which is probably why you lose service) tells me something needs to change. on your i747m, what is your baseband version? also, what is your android/task650 release?

xBeerdroiDx said:
the fact that your gsm device has built in options for cdma and consistently tries switching to cdma (which is probably why you lose service) tells me something needs to change. on your i747m, what is your baseband version? also, what is your android/task650 release?
Click to expand...
Click to collapse
I can't believe I forgot to mention what kind of phone it was its not the Canadian model... I bought the phone off of ebay it is an at&t SGH-I747 the phone already had the custom rom on it when I got it.
The baseband version is i747UCDLK3
Kernel version:
30.0.68-underwear kernel
[email protected] #1
Sun Mar 10
AOKP version
d2att (4.2.2 jdq39) build 3.10.2013

n023b said:
I can't believe I forgot to mention what kind of phone it was its not the Canadian model... I bought the phone off of ebay it is an at&t SGH-I747 the phone already had the custom rom on it when I got it.
The baseband version is i747UCDLK3
Kernel version:
30.0.68-underwear kernel
[email protected] #1
Sun Mar 10
AOKP version
d2att (4.2.2 jdq39) build 3.10.2013
Click to expand...
Click to collapse
oh wow, so you literally just bought that on ebay. unfortunately, when buying a device thats already rooted and running a custom ROM, you dont know the procedures used when that ROM was installed. there's a wrong and right way to do it so as to have a smooth running phone with little or no complications. I would make a backup in recovery and then try a different modem or reflash the ROM and google apps (gapps) again. is the ROM and gapps files (.zips) still on the phone?

xBeerdroiDx said:
oh wow, so you literally just bought that on ebay. unfortunately, when buying a device thats already rooted and running a custom ROM, you dont know the procedures used when that ROM was installed. there's a wrong and right way to do it so as to have a smooth running phone with little or no complications. I would make a backup in recovery and then try a different modem or reflash the ROM and google apps (gapps) again. is the ROM and gapps files (.zips) still on the phone?
Click to expand...
Click to collapse
I updated the rom the other day and had to reinstall gapps so yes I'll try flashing other radios.
I went to *#*#4636#*#* and set the radio to GSM/LTE and the phone still drops the signal and doesnt change to WDCDMA...
Edit: Update it will switch to WCDMA

n023b said:
I updated the rom the other day and had to reinstall gapps so yes I'll try flashing other radios.
I went to *#*#4636#*#* and set the radio to GSM/LTE and the phone still drops the signal and doesnt change to WDCDMA...
Click to expand...
Click to collapse
when you updated, did you perform a full wipe? that might fix this whole issue

xBeerdroiDx said:
when you updated, did you perform a full wipe? that might fix this whole issue
Click to expand...
Click to collapse
Yes I did the full wipe, cache wipe, and dalvik cache wipe.. It still has the same problem after I reflashed I'm going to try and flash different radios now.
If that doesn't work whats the next step reverting back to stock and seeing if that works?

n023b said:
Yes I did the full wipe, cache wipe, and dalvik cache wipe.. It still has the same problem after I reflashed I'm going to try and flash different radios now.
If that doesn't work whats the next step reverting back to stock and seeing if that works?
Click to expand...
Click to collapse
Did you format /system?

try unrooting and going back to stock then rerooting.
That worked for me

xBeerdroiDx said:
Did you format /system?
Click to expand...
Click to collapse
Yes I believe I did I went to the official thread and did what it said there
f_E_a_R_e_D said:
try unrooting and going back to stock then rerooting.
That worked for me
Click to expand...
Click to collapse
I'll try that but weird thing...I remember reading somewhere too many open apps may cause signal problems and I just killed all open apps when the signal dropped and about 15 secs later signal was back dont know if this was the problem for sure I'll try again if it happens see if maybe I can narrow it down to a particular app or process

Note 2 No data coverage after 4.3 update?

Just upgraded to 4.3 today but my data services don't seem to function well. Can someone please help me?

Same problem here..

Looks to be an issue with TWRP, have either of you tried the latest CWM recovery? I was hoping to avoid it since my nandroid backup was TWRP (I'm honestly not sure if there's a difference) but a few posts in the main threads are reporting a similar thing.
EDIT: Nope, same issue, at least for omnirom.
I take that back, it does work.

Go to Settings - Network Connections - More Networks - Mobile Networks - Access Points Names
Check and see if you have the APNs from your provider, they usually are 3 ([Provider] Internet, [Provider] WAP, [Provider] MMS - in my case). Make sure [Provider] Internet is selected. When I usually re-install some ROMs, the WAP APN is selected by default and that will show me the 3G data icon but it will not let me access internet resources with my data services.
If by any chance you are missing the Internet APN, search a bit on the internet for your provider APN settings for internet access.
Hope this works.

lolozaur said:
Go to Settings - Network Connections - More Networks - Mobile Networks - Access Points Names
Check and see if you have the APNs from your provider, they usually are 3 ([Provider] Internet, [Provider] WAP, [Provider] MMS - in my case). Make sure [Provider] Internet is selected. When I usually re-install some ROMs, the WAP APN is selected by default and that will show me the 3G data icon but it will not let me access internet resources with my data services.
If by any chance you are missing the Internet APN, search a bit on the internet for your provider APN settings for internet access.
Hope this works.
Click to expand...
Click to collapse
It just acts like there's no SIM card at all. I don't understand it completely, but CWM is doing something that TWRP is not (or vice versa) and is causing this issue. Took my 7105T from virgin vanilla stock to the omnirom 4.4.2 nightlies yesterday and when I flashed from CWM the issue was resolved.
That said though, I'm unsure how this will affect omnirom's updates so I might need to switch to cyanogenmod. Shame, because I do prefer TWRP.

BadKingDookie said:
It just acts like there's no SIM card at all. I don't understand it completely, but CWM is doing something that TWRP is not (or vice versa) and is causing this issue. Took my 7105T from virgin vanilla stock to the omnirom 4.4.2 nightlies yesterday and when I flashed from CWM the issue was resolved.
That said though, I'm unsure how this will affect omnirom's updates so I might need to switch to cyanogenmod. Shame, because I do prefer TWRP.
Click to expand...
Click to collapse
try to change different modems.
i hope it will work
dont worry, it happened to me also

Kindly check ur imei if its generic 0034*****
I got the same problem also
Sent from my GT-N7100 using xda premium

try to revert to original stock rom

sabharwalrahul91 said:
Kindly check ur imei if its generic 0034*****
I got the same problem also
Sent from my GT-N7100 using xda premium
Click to expand...
Click to collapse
Try to change modems.

ken_alpha24 said:
Just upgraded to 4.3 today but my data services don't seem to function well. Can someone please help me?
Click to expand...
Click to collapse
try to factory reset your device
it seems you missing your IMEI
it happens in some device,,,
or if you still have warranty just go to your retailer

Problem solved. Got to the service center to reflash FW. Ty guys
Sent from my GT-P3110 using xda app-developers app

cant access apn settings after 4.3 update
ken_alpha24 said:
Problem solved. Got to the service center to reflash FW. Ty guys
Sent from my GT-P3110 using xda app-developers app
Click to expand...
Click to collapse
I don't know what you guys are talking about but I can't even access the APN settings, its invisible. I have a SCH R950 note 2. H2o wireless already took my money but told me I needed to unlock it, even though I can't unlock a CDMA phone. im so confused because it is quad band and has sim card slot but no one can unlock it and I cant find how to flash to h20

[Q] G3 / 20F No LTE?

Im using a D855 LG G3 running the bumped v20F stock firmware (see the android dev thread) with no issues except this one...
Im currently in singapore using a SIM card that supports 4G on a network that has good 4G coverage (M1) but i simply cannot get LTE/4G to work at all.
Ive tried the WCDMA/LTE/GSM/Auto in mobile settings and it always without fail sticks on "H". Via the hidden menu i select "LTE Only" and i get no data connection icon (or data) at all.
Searching the mobile networks ive tried manually selecting the M1 advertising as LTE on the list but the same thing - it defaults to "H" and wont shift off there.
The APN im using is the one advertised by M1 for 3G and 4G coverage.
I dont think this is a ROM problem hence posting it here but ive got no idea how to solve it. Anyone got any ideas what else i can do/change or check ?
Other than rooted, the stock ROM is not modified or customised in any way - it was a factory reset, clean install.

Similar issue in Argentina, with 20b on my D855. Tried using the 3845#855# code, selecting even the LTE only thing, but nothing, no LTE. SIM card and service is working right (tested on a Nexus 5).
Any thoughts would be appreciated.

alex_herrero said:
Similar issue in Argentina, with 20b on my D855. Tried using the 3845#855# code, selecting even the LTE only thing, but nothing, no LTE. SIM card and service is working right (tested on a Nexus 5).
Any thoughts would be appreciated.
Click to expand...
Click to collapse
Try reinstalling LTEConfigs.apk under system/app

Unfortunately, I can't root or flash anything on this phone until I know it can use our LTE bands, or should I return it. Any other way?

[Q] disappeared LTE all firmware

What is done:
first I flash 30B bump, the problems starte. then flash 30B LGUp, flash 21a and 21c, change band in ingeneering menu, delete lteconfig, flash 30b bump with modems: 21a, 21c, 30b hybrid, change of operator, manual config APN, manual search network. All this does not help.
Any ideas?

no ideas?

Idem.
But after reboot 4G is ok, but again...every morning i lost signal 4G...only 2G/3G is ok. So..reboot & 4G is up......disappointed.

Same on my G3. I downgrade from MM to LP but problem persist.

Same here....tried rollback to kitkat stock, LP stock, CM12, Cm13, and some other roms with no luck....have just flashed stock LP for repair...

so today I tried swapping my SIM with my friend's
he is using G3 with stock 21A, and his SIM is of the same carrier as mine
after swapping, I found that my phone (and of course his phone, too) is working normally
my phone is normal even after swapping back
did some different tests like switching on and off with 3G, LTE etc., everything is normal, at least at this moment

Still working with you? So it is sim card fault? With me after searching networks everything seems to be ok, but I couldn't connect with LTE. Only sometimes successfull connection.(once a day and after reboot same...) Very strange. :/

I lost network signal randomly... i tried with 30b hybrid modem, 21a, 21c... kdz method, twrp bumped rom... and doesnt help me at all.. my network signal gets a rotating circle randomly... and in that time my phone is out of coverage... it is .... hundred times in a day... i dont know what to do, please help

same here when i use sucks 30b D855, but now everything is ok with me.
Steps that have been followed:
downgrade to lollipop 5.0
install CandySIX Rom , then try to connect to my carrier network , at the first time it not give me anything , but when i reboot my phone , LTE appears and everything fine
back to CloudyG3 2.5 then i found that the problem resolved
My phone now works well

OKAY, i found a solution to the problem and here is what i found :
Pacote-san said:
Same here...
Edited: Fixed this deletings the folder LTEconfigs on System/app
Had to then configure it to auto GSM/WCDMA then switch back to LTE auto
It connected at first with 3g then it went LTE and worked normally
Click to expand...
Click to collapse
i made it and not i have no drop in connection and i am sure that i will receive the next important call from my colleges.
I hope that this help you as it helped to me!
All the best!

goly1993 said:
Still working with you? So it is sim card fault? With me after searching networks everything seems to be ok, but I couldn't connect with LTE. Only sometimes successfull connection.(once a day and after reboot same...) Very strange. :/
Click to expand...
Click to collapse
Some people got their phones back to normal by flashing some roms (like CM, ACIP, stock, etc.), but that didn't work for mine
not sure if it was sim card fault, but my problem solved (at that time i was back to LP stock 20h) after swapping my sim cards with my friend's.
i am still using that sim card at this moment, working fine since last thursday

Same problem here, have signal drops on MM roms with LTE connection.
Tried all methods above, nothing really helps .. ;((
The signal is fine on LP roms, tho i installed N&N so i was able to change network type to GSM/WCDMA auto, having steady signal now, but missing LTE speed, trying to find solution to fix this, but unfortunately for now.

Same, my G3 doesn't recognize my sim sometimes or it just loses signal randomly, making the smartphone almost useless.
I tried CloudyG3 2.5 Lollipop, then upgrading to Marshmallow with many radios flashed (also the hybrid one) , then I tried to come back to a stock Lollipop ROM and the signal is always unstable. I'm going crazy due to that. I'm starting to lose hope too.

I think I've tried every possible solution to the connectivity problems I've read since flashing 30b.
Freezing LteConfigs gave me more stability, but didn't solve the problem completely. Tried editing the build.prop to force LTE as preferred network type, this didn't change anything. Don't even know how many times I've changed my apn settings.
Tried every combination of modems possible: 21a/c modem with 30b rpm/tz, pure 21a/c, pure brazilian 20c, brazilian 20c with 30b rpm/tz and nothing. Changed sims multiple times, didn't work.
The only way to get a reliable connection is to limit the phone to 3G... but that isn't a solution since I pay for unlimited 4G. If I let the phone in auto mode, the instant it tries to connect I lose all connectivity and it would take up to 2 minutes searching for the network.
I'll flash the stock rom today and if it doesn't work I can safely say it should be a hardware problem.

soulstaker said:
I think I've tried every possible solution to the connectivity problems I've read since flashing 30b.
Freezing LteConfigs gave me more stability, but didn't solve the problem completely. Tried editing the build.prop to force LTE as preferred network type, this didn't change anything. Don't even know how many times I've changed my apn settings.
Tried every combination of modems possible: 21a/c modem with 30b rpm/tz, pure 21a/c, pure brazilian 20c, brazilian 20c with 30b rpm/tz and nothing. Changed sims multiple times, didn't work.
The only way to get a reliable connection is to limit the phone to 3G... but that isn't a solution since I pay for unlimited 4G. If I let the phone in auto mode, the instant it tries to connect I lose all connectivity and it would take up to 2 minutes searching for the network.
I'll flash the stock rom today and if it doesn't work I can safely say it should be a hardware problem.
Click to expand...
Click to collapse
I had exactly the same problems I tried all of the solutions mentioned modems/roms/etc but what solved it for me was flashing the Pure stock MM kdz now no signal drops or 4g problems.

tallman43 said:
I had exactly the same problems I tried all of the solutions mentioned modems/roms/etc but what solved it for me was flashing the Pure stock MM kdz now no signal drops or 4g problems.
Click to expand...
Click to collapse
Did you root after flashing the kdz? I'll try with pure 30B but having no root is almost as bad as no 4G.

soulstaker said:
Did you root after flashing the kdz? I'll try with pure 30B but having no root is almost as bad as no 4G.
Click to expand...
Click to collapse
No not rooted it yet, to be honest I don't like the kingroot app it looks way too suspicious to me + the rom is smooth and stable at the moment so I thought I would stick with stock for a while.
Sent from my LG-D855 using Tapatalk

You could take a look on this : http://forum.xda-developers.com/lg-g3/help/annoying-lg-g3-problem-lte-signal-solved-t3293721
This is my answer to this mass problem. Hope this help yo all you !

mccloud90 said:
You could take a look on this : http://forum.xda-developers.com/lg-g3/help/annoying-lg-g3-problem-lte-signal-solved-t3293721
This is my answer to this mass problem. Hope this help yo all you !
Click to expand...
Click to collapse
This worked for me after nothing else had. Thanks a lot!
Sent from my LG-D855 using Tapatalk

adamw said:
This worked for me after nothing else had. Thanks a lot!
Sent from my LG-D855 using Tapatalk
Click to expand...
Click to collapse
just say thanks into that thread and vote to be able to other members to be sure that this helps. I am so happy that this method helped you. HF

No 4G

I've searched and tried the suggestions here and installed creepers (very cool) and still only 3g I'm on the latest Emotionos on my 910v with newest twrp. This is a great rom and I donated anyway but has anyone had any luck getting the 4 g back?

sportytony said:
I've searched and tried the suggestions here and installed creepers (very cool) and still only 3g I'm on the latest Emotionos on my 910v with newest twrp. This is a great rom and I donated anyway but has anyone had any luck getting the 4 g back?
Click to expand...
Click to collapse
Do a full firmware flash. Use the clp1 without recovery and aboot. That's the god fix. Then flash your rom again. All good.

sportytony said:
I've searched and tried the suggestions here and installed creepers (very cool) and still only 3g I'm on the latest Emotionos on my 910v with newest twrp. This is a great rom and I donated anyway but has anyone had any luck getting the 4 g back?
Click to expand...
Click to collapse
flash this then in settings go to more under wireless & networks then mobile networks then access point names then in the three dot menu reset to default and reboot your phone

weard1212 said:
flash this then in settings go to more under wireless & networks then mobile networks then access point names then in the three dot menu reset to default and reboot your phone
Click to expand...
Click to collapse
Thank you thank you! Worked like a charm! I thought I searched everywhere and was freaking that I was gonna have to start from scratch. But this was perfect. I hope someone else finds this and thanks you.

weard1212 said:
flash this then in settings go to more under wireless & networks then mobile networks then access point names then in the three dot menu reset to default and reboot your phone
Click to expand...
Click to collapse
After I flash the zip, should I still wipe dalvich cache before rebooting? Thanks

dhplap said:
After I flash the zip, should I still wipe dalvich cache before rebooting? Thanks
Click to expand...
Click to collapse
no, its not necessary for this.

Worked for me as well(!)
Flashing LTEfix.zip, then resetting networks to default worked for me as well.
Samsung N910V (trtlevzw) EmotionOS 20170129-OFFICIAL Baseband (modem) N910VVRU2CPF3.
Was only seeing 3G, now see 4G. Not sure if that's a change in indicators or actual 4G (LTE-A), but it seems to have worked.
Thanks!

weard1212 said:
flash this then in settings go to more under wireless & networks then mobile networks then access point names then in the three dot menu reset to default and reboot your phone
Click to expand...
Click to collapse
Hi, I was wondering if you could point me in the direction of the thread where the lte fix came from. I just want to do a little more reading on it. Thanks

There are no words, weard1212! I owe you a beer or pizza! I was gonna have to buy a N4 off swappa since losing 4g a week ago. THANK YOU SO MUCH SIR! The ltefix got my 4g back!!!
I do have a new issue though. I'm on emotionOS build 20170328, baseband cfp3 as well. In global network mode I still only get 3g, but 4g works fine when I switch to wcdma/lte. Even weirder: in the expanded pull down notification bar it says "no service" where it should say "Verizon wireless" under the cellular data quick tile button (4g still works though). Any ideas, I'm almost back to being perfect! Thanks again friend!

okay so I can't send texts over lte/cdma? They work on global/3G but not when I have 4g. I'm certain this can be fixed and that's it not hardware. Please, anybody have experience or opinions? Ran the flash twice now, reset apn, network settings and restored nandroids. On global mode under apns it's blank, "the apns for this user cannot be displayed". Flash a different modem perhaps?

weard1212 said:
flash this then in settings go to more under wireless & networks then mobile networks then access point names then in the three dot menu reset to default and reboot your phone
Click to expand...
Click to collapse
Old thread but if you are still around do you know what file the binary in this zip is replacing?

droidzer1 said:
Old thread but if you are still around do you know what file the binary in this zip is replacing?
Click to expand...
Click to collapse
system/etc/apns-conf.xml