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[Q] Nexus S no network service! What do I do?

Hi guys I have a 2 month old Nexus S and for no apparent reason all of a sudden today I noticed I am not getting any network service (australia vodafone).
I've tried removing and trying other sim cards which are known to work. My sim card works in other phones so it's nothing wrong with the sim card. Wifi still works perfectly. I've tried going in and out of airplane mode to restart the antenna and I've tried to turn it off and on again. I've also done a factory reset and erased all data through the android menu as well as the bootloader separately to no avail.
However what I also noticed is even though I did factory resets it doesn't seem to completely reset it as the android version still shows 2.3.3 which I applied using a manual update. The phone had 2.3.1 when I bought it. How do I do a full reset to send it back to 2.3.1?
The phone is still under warranty however if it is a software issue I would rather fix it myself then send it away.

I'm having the same issue. I've posted in the cyanogen forums but I'll share the issue here as well.
I'm pretty scare the radio is damaged or something...
I've rebooted my Nexus S with Cyanogen RC4 to show a friend of mine the boot animation. From that point on, I'd get messages that the application "com.android.phone" force crashed all the time.
I noticed at that point that I had no signal/radio/service.
Wifi worked properly and still works fine.
I've tried updating Cyanogen to the stable release, still no service but I stopped getting the phone crashing errors.
Tried flashing a new radio (KB3) through clockwork recovery, didn't fix the problem.
Tried flashing stock back (2.3.3 Deodexed unrooted) didn't work.
Made sure data and cache was wiped, didn't fix the issue.
I've also tried relocking and re-unlocking the device (oem lock, oem unlock), to no avail.
As a last resort, attempted to enable and disable airplane mode but no go either.
I'm pretty scared that the radio might be damaged (how would it have been damaged by a simple reboot ?) How can I tell and what further steps can I take to diagnose this ?
Right now, I'm trying to reflash cyanogen so that I try and get a dmesg on the device.
Thanks,

Additionnal bit of info.
Someone on Cyanogen forums asked me to try to flash the radio through fastboot instead of clockwork recovery..
If I do that, it is able to send the file but it seems unable to write. It gets stuck here:
fastboot flash radio XXKB1-GRI40-radio-nexuss-unsigned.zip
sending 'radio' (4126 KB)... OKAY
writing 'radio'...
(I've tried flashing both KB1 and KB3 through flashboot, same results)

Hello everyone,
I have the same issue. I turned my phone on this morning and it said "no service, emergency call only".
I used wifi to apply the OTA 2.3.4 with hope that it'd fix the issue as I read from my google searches. But it does not.
I tried flashing back to KB3 to run with 2.3.4 as well but that doesn't help.
If the phone can still do emergency call, it means the hardware is OK, right?
any suggestion? Thank you very much.
Opteron.

Did anyone ever find a solution?

you could try dialing *#*#4636#*#*, going to phone information, and looking at your preferred network type (might be the wrong one). you could also go to phone information, push menu, go to select radio band, and try a few different ones. hopefully that solves it, or you might have to flash a different radio/rom
edit: make sure you write down the original preferred network type before you change it. it could screw with what kind of service you get if you set it to the wrong one

Hi,
I am having the similar problem with my Nexus S
Tried the *#*#4636#*#* settings to EURO and GSM only but with no success.
Did anyone ever find a solution?

hi, im just wondering what type of root did you use for the AU nexus s. im not sure what root method to use for the SCLCD :S
thanks

fooraide said:
I'm having the same issue. I've posted in the cyanogen forums but I'll share the issue here as well.
I'm pretty scare the radio is damaged or something...
I've rebooted my Nexus S with Cyanogen RC4 to show a friend of mine the boot animation. From that point on, I'd get messages that the application "com.android.phone" force crashed all the time.
I noticed at that point that I had no signal/radio/service.
Wifi worked properly and still works fine.
I've tried updating Cyanogen to the stable release, still no service but I stopped getting the phone crashing errors.
Tried flashing a new radio (KB3) through clockwork recovery, didn't fix the problem.
Tried flashing stock back (2.3.3 Deodexed unrooted) didn't work.
Made sure data and cache was wiped, didn't fix the issue.
I've also tried relocking and re-unlocking the device (oem lock, oem unlock), to no avail.
As a last resort, attempted to enable and disable airplane mode but no go either.
I'm pretty scared that the radio might be damaged (how would it have been damaged by a simple reboot ?) How can I tell and what further steps can I take to diagnose this ?
Right now, I'm trying to reflash cyanogen so that I try and get a dmesg on the device.
Thanks,
Click to expand...
Click to collapse
Hello! did you find any solution or you repaired your nexus s? Im having the same problem. when i try to back to stock from Cyanogen..Any suggestion? Regards

found a solution
hi guys ! I recently had the same trouble that no signals were being received after updating to 4.1.2 but then i dialed *#*#4636#*#* and turned off the radio and turned it on again and now its all fine

[Q] No Mobile Data

I'm kind of worried at this point. After looking through some threads I found with a search for a similar problem I'm going to make my own.
Problem: No data at all. About section of phone says:
Network: Unknown
Mobile network type: Unknown
Service state: Out of service
Mobile network state: disconnected
I do still have an IMEI.
It happened in the middle of normal operation, browsing the web with stock browser with CM10.1 (4.2) with the 1/20 nightly.
What I've tried: Already reset SIM card, toggled Mobile Data and everything data related I can find in the Settings menu. I've data wiped and flashed the same nightly through recovery along with the same gapps .zip that was all working halfway through the day. I got home from work and tried using Odin to flash back to a pre-rooted full wipe 4.1.1 ROM found using this thread: http://forum.xda-developers.com/showthread.php?t=1984436
The first time it booted up to the stock startup screen and just hung. Cleared data through recovery, booted into Odin and tried again and it booted up, but still no data. That's where I am now. I just don't know what else to try. I see some stock radio flash instructions but I'm really not sure what that accomplishes if I'm already flashing stock ROMs. The trouble is I know just enough about this to break stuff.
Does anyone have any recommendations or ideas?

hextlol said:
I'm kind of worried at this point. After looking through some threads I found with a search for a similar problem I'm going to make my own.
Problem: No data at all. About section of phone says:
Network: Unknown
Mobile network type: Unknown
Service state: Out of service
Mobile network state: disconnected
I do still have an IMEI.
It happened in the middle of normal operation, browsing the web with stock browser with CM10.1 (4.2) with the 1/20 nightly.
What I've tried: Already reset SIM card, toggled Mobile Data and everything data related I can find in the Settings menu. I've data wiped and flashed the same nightly through recovery along with the same gapps .zip that was all working halfway through the day. I got home from work and tried using Odin to flash back to a pre-rooted full wipe 4.1.1 ROM found using this thread: http://forum.xda-developers.com/showthread.php?t=1984436
The first time it booted up to the stock startup screen and just hung. Cleared data through recovery, booted into Odin and tried again and it booted up, but still no data. That's where I am now. I just don't know what else to try. I see some stock radio flash instructions but I'm really not sure what that accomplishes if I'm already flashing stock ROMs. The trouble is I know just enough about this to break stuff.
Does anyone have any recommendations or ideas?
Click to expand...
Click to collapse
SOLUTION: Settings > Mobile Network > Network Mode - was set to GSM/UMTS in 4.1.1 pre-rooted ROM. changed to LTE/CDMA and resolved. Can't believe I overlooked that.
Thanks.

No cell signal, wifi works

My Nexus 5 suddenly has no signal today, but WIFI is working (my nexus tab has a cell signal so its not a network issue.)
was using CM12.1 (5.02) tried the following:
reboot (many times)
did a factory reset/wipe
flashed a new CM rom (Euphoria 1.1)
hit *#*#4636#*#* and checked the radio is on
popped the back and cleaned the antenna contacts
None of the above worked, now I'm wondering what to do next...?
Any suggestions would be gratefully appreciated.

sleepingsword said:
My Nexus 5 suddenly has no signal today, but WIFI is working (my nexus tab has a cell signal so its not a network issue.)
was using CM12.1 (5.02) tried the following:
reboot (many times)
did a factory reset/wipe
flashed a new CM rom (Euphoria 1.1)
hit *#*#4636#*#* and checked the radio is on
popped the back and cleaned the antenna contacts
None of the above worked, now I'm wondering what to do next...?
Any suggestions would be gratefully appreciated.
Click to expand...
Click to collapse
Flash factory images.

Sim card issue?

Turn off airplane mode lol

sleepingsword said:
My Nexus 5 suddenly has no signal today, but WIFI is working (my nexus tab has a cell signal so its not a network issue.)
was using CM12.1 (5.02) tried the following:
reboot (many times)
did a factory reset/wipe
flashed a new CM rom (Euphoria 1.1)
hit *#*#4636#*#* and checked the radio is on
popped the back and cleaned the antenna contacts
None of the above worked, now I'm wondering what to do next...?
Any suggestions would be gratefully appreciated.
Click to expand...
Click to collapse
Do you have an IMEI (Settings>About phone>Status)?

IMEI is present
Airplane mode is off :silly:
Sim card is fine, I tested it in my old i9300
I guess I will go factory image later today and see about that.
Thx so far.

Well it appears the fone is dead...
I restored a factory image (4.4.0)
Still no cell signal.
Going through the updates 4.4.2 > 4.4.3 etc, but I doubt its going to make a difference.
Bought in 2013... I hope (but doubt) I can get it fixed under warranty

sleepingsword said:
Well it appears the fone is dead...
I restored a factory image (4.4.0)
Still no cell signal.
Going through the updates 4.4.2 > 4.4.3 etc, but I doubt its going to make a difference.
Bought in 2013... I hope (but doubt) I can get it fixed under warranty
Click to expand...
Click to collapse
It's not enough to restore factory image. Try to flash completely stock. http://forum.xda-developers.com/google-nexus-5/general/tutorial-how-to-flash-factory-image-t2513701

Sorry for my wording, I went completely back to stock and unfortunately it did not fix the issue.
It is still covered under warranty and with the stock restore its is now ready to be sent back.
Back to the old i9300 for now!

sleepingsword said:
Sorry for my wording, I went completely back to stock and unfortunately it did not fix the issue.
It is still covered under warranty and with the stock restore its is now ready to be sent back.
Back to the old i9300 for now!
Click to expand...
Click to collapse
After you flash back to stock, what steps are you taking when setting up the phone again - are you restoring app backups and stuff? I had this same problem, when I restored as new and did not use the google backups, my radio/mobile network returned.

I dint bother setting up my accounts or restoring backups as I expected it not to work.
I did not want to bring unforeseen things into the mix.
Restored 4.4, made sure it was unrooted and the tamper counter was reset. locked the bootloader.
Then skipped the google account part, only added wifi password. Then went through the system updates.

sleepingsword said:
I dint bother setting up my accounts or restoring backups as I expected it not to work.
I did not want to bring unforeseen things into the mix.
Restored 4.4, made sure it was unrooted and the tamper counter was reset. locked the bootloader.
Then skipped the google account part, only added wifi password. Then went through the system updates.
Click to expand...
Click to collapse
Mine did the same thing (worked for phone/texts but not mobile data), and in my searching there seems to be a related fix having to do with APN settings, but those are only accessible in settings, under mobile network, if you have a specific carrier.
Try searching around here for "APN XML" or "APN update" and you'll find steps on how to check/fix. Hope that helps.

No cellular connectivity whatsoever

So I've been flashing back and forth and restoring nandroids the entire day trying to troubleshoot and get xposed to work for 5.1. As of now, I've lost all cellular connectivity as in no cell service at all. Thought it may be my sim but I tried it out on my old Xperia Z1s and it works fine, sent text and tried downloading something from play store. Both worked fine so it's not the sim card (Tmo). I've been flashing and restoring both CM12 (last one available through the updater) and CM12.1 (4/18 nightly and just now 4/19 to try). Wifi works fine but there's no cellular signal/service. It's not acting as if there's no sim, it's acting as if there's no service at all, not even emergency cell signal. My guess is my modem is fried so I tried to flash the latest modem from XNPH44S but that didn't work either. I've searched the forums and googled but no one seems to have my exact issue. Most were either of stuck airplane mode or issues with APN settings. I'd be more relaxed if those were my issues as I'm really hoping I didn't fry my modem (hardware) flashing back and forth all day. Any suggestions?

gqukyo said:
So I've been flashing back and forth and restoring nandroids the entire day trying to troubleshoot and get xposed to work for 5.1. As of now, I've lost all cellular connectivity as in no cell service at all. Thought it may be my sim but I tried it out on my old Xperia Z1s and it works fine, sent text and tried downloading something from play store. Both worked fine so it's not the sim card (Tmo). I've been flashing and restoring both CM12 (last one available through the updater) and CM12.1 (4/18 nightly and just now 4/19 to try). Wifi works fine but there's no cellular signal/service. It's not acting as if there's no sim, it's acting as if there's no service at all, not even emergency cell signal. My guess is my modem is fried so I tried to flash the latest modem from XNPH44S but that didn't work either. I've searched the forums and googled but no one seems to have my exact issue. Most were either of stuck airplane mode or issues with APN settings. I'd be more relaxed if those were my issues as I'm really hoping I didn't fry my modem (hardware) flashing back and forth all day. Any suggestions?
Click to expand...
Click to collapse
Try restoring via fastboot for a clean slate. I understand from your post that you're flashing via custom recovery.

gqukyo said:
So I've been flashing back and forth and restoring nandroids the entire day
Click to expand...
Click to collapse
CM12.1 may flash the new radio that OxygenOS flashes, from which there is not necessarily an immediate return.
Possible you have that new radio. See here:
https://forums.oneplus.net/threads/oxygenos-back-to-cm11s.296219/#post-10851703

gqukyo said:
So I've been flashing back and forth and restoring nandroids the entire day trying to troubleshoot and get xposed to work for 5.1. As of now, I've lost all cellular connectivity as in no cell service at all. Thought it may be my sim but I tried it out on my old Xperia Z1s and it works fine, sent text and tried downloading something from play store. Both worked fine so it's not the sim card (Tmo). I've been flashing and restoring both CM12 (last one available through the updater) and CM12.1 (4/18 nightly and just now 4/19 to try). Wifi works fine but there's no cellular signal/service. It's not acting as if there's no sim, it's acting as if there's no service at all, not even emergency cell signal. My guess is my modem is fried so I tried to flash the latest modem from XNPH44S but that didn't work either. I've searched the forums and googled but no one seems to have my exact issue. Most were either of stuck airplane mode or issues with APN settings. I'd be more relaxed if those were my issues as I'm really hoping I didn't fry my modem (hardware) flashing back and forth all day. Any suggestions?
Click to expand...
Click to collapse
Can you still see your baseband and IMEI? Go into Settings/About Phone for the baseband version and Settings/About Phone/Status for the IMEI.
Transmitted via Bacon

Baseband is unknown and there's no mention of IMEI anymore... does that mean I lost my IMEI/it got corrupted? Am I screwed? I planned on trying the fastboot restore but only as one of the last resorts. If CM12.1 use the same radio then my 12.1 should work but that doesn't either. Nothing works. I've tried CM11s, CM12, CM12S, CM12.1... sigh...
I think I had a modem/efs backup in one of my nandroids and I tried restoring that too with no luck
Restored one of my CM12 nandroids and now I have a baseband of "DI.3.0.c6-00230-M8974AAAAANAZM-1". For some reason or another, that doesn't look right to me even though I've never really paid attention to what the baseband ever listed. Still can't seem to locate my IMEI #. I did the #*#*4636*#*# and the cell radio is on and turning it off and one still only shows emergency calls only. Obviously I'm not going to try to call 911 just to test if the radio gets service. However, I can see my IMEI # so I guess that's good. I must have some bad firmware update. Guess I'll copy out all my stuff to my otg usb and fastboot restore and see if that helps unless there's something else I can try.... please let me know...

gqukyo said:
Baseband is unknown and there's no mention of IMEI anymore... does that mean I lost my IMEI/it got corrupted? Am I screwed? I planned on trying the fastboot restore but only as one of the last resorts. If CM12.1 use the same radio then my 12.1 should work but that doesn't either. Nothing works. I've tried CM11s, CM12, CM12S, CM12.1... sigh...
I think I had a modem/efs backup in one of my nandroids and I tried restoring that too with no luck
Restored one of my CM12 nandroids and now I have a baseband of "DI.3.0.c6-00230-M8974AAAAANAZM-1". For some reason or another, that doesn't look right to me even though I've never really paid attention to what the baseband ever listed. Still can't seem to locate my IMEI #. I did the #*#*4636*#*# and the cell radio is on and turning it off and one still only shows emergency calls only. Obviously I'm not going to try to call 911 just to test if the radio gets service. It really does look like it's my IMEI # that got jacked... what can I do now?.... :T
Click to expand...
Click to collapse
You've got a corrupt EFS partition. There's a thread detailing how to fix your situation in our general section.
Transmitted via Bacon

tried to flash the persist.img from http://forum.xda-developers.com/oneplus-one/help/fix-brickloop-audio-fx-fc-efs-corrupt-t2879061 but that just prevents my phone from booting up properly. I only see the OnePlus logo with not Powered by Android on the bottom...
I take it back, it does show the powered by android but only for a split second then it stays on the OnePlus logo and doesn't do anything... :T
Restored back most recent cm12.1 nandroid and now I do see IMEI number in the about settings but still only emergency calls only... Guess its a good start, no sure what else I can do at this point.

Now you see your imei but you dont have the signal,it means your modem file does not work.So the first thing to do is backing up the efs then you can flash 44s modem and proximity patch.Probably it will work.It worked for me.

Ok there may be hope then. Just flashed the 44s modem then nandroided back to my CM11s then flashed modem again just in case lol. Don't recall seeing a proximity fix but it's ok as long as my cellular connectivity works, I'll deal w/ other issues later. Otherwise all I have is an expensive media player... lol it's booting up now so we'll see... *fingers crossed*
Nope didnt work...going to try a fresh CM12 install...
Trying to flash roms and in the wizards it always states I don't have a sim installed so I'm not sure it's my modem that's messed up or if it's something else related to hardware related to the sim. The sim itself works in my other phone... tried a different sim and it's still emergency calls only. don't know what to do now. doing all this and it's still not working so I doubt even the fastboot restore would work... might just have to rma... which would probably take 4eva...

Pls flash your nandroid backup which gave you the imei first,after gain your imei ,back up it,then you can flash what rom you like,if you dont have your imei,just flash your imei backup.The most important thing is to back up your efs.
Sent from my A0001 using XDA Free mobile app

Think my efs is fine as I can see the IMEI now but no matter what nandroid and fresh install I try, I can't get the cellular connectivity to work. I backed up all partitions just in case.

gqukyo said:
Think my efs is fine as I can see the IMEI now but no matter what nandroid and fresh install I try, I can't get the cellular connectivity to work. I backed up all partitions just in case.
Click to expand...
Click to collapse
Being able to see your IMEI doesn't necessarily mean your EFS is ok.
Transmitted via Bacon

Well tried the persist.img but that didn't work so what else can I do?

The one thing that would definitely fix your issues would be if you had an EFS backup. I don't know why people don't do this. Without that I have no idea what you can do.
Transmitted via Bacon

Never had that issue before and I've own android phones from the HTC Hero. Lesson learned though, thankfully it's still under warranty and it's not that expensive a phone...

gqukyo said:
Never had that issue before and I've own android phones from the HTC Hero. Lesson learned though, thankfully it's still under warranty and it's not that expensive a phone...
Click to expand...
Click to collapse
Not all Android phones employ an EFS partition. I'd never heard of it before this phone but a bit of research on my part revealed the importance of an EFS backup.
Transmitted via Bacon

That would make sense then. As I was reading about EFS, seems like it was mostly Samsung phones. I guess I can try a fastboot restore... nothing else to lose. lol
Doh! apparently there is something to lose when fastboot restoring... phone stopped booting back up correctly after a few fastboot restores and now it won't even turn back on... lovely... at least I had a expensive android media player before, now I have a brick... lol

Edited - Sorry

I have the same issue with all verisons of CM12. I get No service. Although the XNPH44S radio was the best. Meaning I could atleast see 3-4 bars for about 1 second and then off for a couple of minutes and then back on again for 1 second and so on. I believe it is a problem with not having a proper radio. One plus should release a better working radio in my opinion. I am on PTEL Mobile network (uses T-Mobile). So until we get a good working version of the radio I think some people like us are stuck on cm11.

No mobile data after flash. Nothing will bring it back

>> Partial solution was found; still looking for the root of the problem. <<
I recently decided to take the plunge and root my OnePlus One and install sultanXDA's CM 13 ROM on it. It was all going well until I booted up into the ROM and discovered that I couldn't get any mobile data. Everything else was working, calling, texting, wifi, but mobile data seemed to refuse to work. Since I initially flashed sultan's ROM with TWRP 3.0.0, I suspected it was a problem with my modem. Though unable to install TWRP 2.8.6.0 to re-flash everything, I did still flash a new modem via ADB. This didn't help.
I have tried many things to fix this. I rebooted/reflashed. I flashed different ROMs. I tried flashing on TWRP 2.8.6.1, though I believe that one has the same modem problem as the versions after it. As mentioned above I tried flashing a modem over ADB. I took out and re inserted my SIM card. In the end, I tried this guide here to restore my phone to it's original state. The guide flashes the stock versions of everything via ADB. Though it did return me to unrooted COS 12.1, it was not able to resolve my data problem.
After the total reset, all I can think that could be causing it is a hardware problem or that it is caused by something not reset in the 100% restore above.
If any of y'all can help my solve this, or at least offer insight, I would be very grateful.
Preemptive Edit I Guess: This thread was just suggested to me while writing this. I'm going to try the solution here and report back. It's OnePlus' reset to stock method. I'm not expecting much after my first 100% reset attempt, but we'll see.
EDIT: Ok, so the solution above fixed my problem... (edit again: turned out to only be a partial solution. See below.)
I would feel really dumb right now if it weren't for the fact that I slaved over this problem for a good ~8 hours before writing this post. Anyways, I'm not sure how to delete this post or mark it as solved. Sorry for the trouble y'all.

Never delete this post !!
I have the same problem, and I spent much more time to find a solution.
I will try this and will update.
Is it a clean stock rom?
Edit:
Didn't help for me ..
Still the same problem, No mobile internet connection.
Thx anyway.

Yeah, actually I was too hasty is identifying this as the solution. For me, the stock reset brought me back to CM 11 which didn't have a problem with mobile data. But if I try to flash a later ROM or update via OTA, the problem returns. I'm still trying to figure out what is causing it. The only information I can find points to it being a modem problem or APN problem, but I'm sure I have sufficiently checked both of those already.
Either way, I'll keep looking. If I find something I'll return here with it. Good luck

arkasa said:
Yeah, actually I was too hasty is identifying this as the solution. For me, the stock reset brought me back to CM 11 which didn't have a problem with mobile data. But if I try to flash a later ROM or update via OTA, the problem returns. I'm still trying to figure out what is causing it. The only information I can find points to it being a modem problem or APN problem, but I'm sure I have sufficiently checked both of those already.
Either way, I'll keep looking. If I find something I'll return here with it. Good luck
Click to expand...
Click to collapse
Try this:
1) Download the latest fastboot images from here: http://forum.xda-developers.com/oneplus-one/general/official-cm11s-roms-ota-updates-t2906746
2) Go here and follow step #8: http://forum.xda-developers.com/oneplus-one/general/guides-bacon-timmaaas-how-to-guides-t2839471
3) Then follow step #2 to install a new recovery (you need to make sure to use TWRP 3.0.0 or the unofficial TWRP if you want to flash modems/firmwares correctly)
4) Download the latest ROM of your choice and install via your recovery

ryanmat said:
Try this:
1) Download the latest fastboot images from here: http://forum.xda-developers.com/oneplus-one/general/official-cm11s-roms-ota-updates-t2906746
2) Go here and follow step #8: http://forum.xda-developers.com/oneplus-one/general/guides-bacon-timmaaas-how-to-guides-t2839471
3) Then follow step #2 to install a new recovery (you need to make sure to use TWRP 3.0.0 or the unofficial TWRP if you want to flash modems/firmwares correctly)
4) Download the latest ROM of your choice and install via your recovery
Click to expand...
Click to collapse
I gave this a try, but booting up after step 3 I still had the same problem. If I understand this method correctly, I think it is essentially the same as the other full restore methods I tried.
I think I may have found the problem though. I was looking at OnePlus' guide to installing OxygenOS. In it they said, "do not try to flash this build through TWRP. You will most likely lose your radio and IMEI which means a trip to our customer support." At this point I have repeatedly reset/restored my modem/radio so I don't think that is the problem, but I haven't seen anything about IMEI before. The IMEI is apparently stored in the EFS partition which as far as I can tell, is not touched by any of the restore methods I have tried. I took a look at my IMEI (about phone -> status) and it turns out my IMEI SV is 00. It's supposed to be a 16 digit number. I found a guide to fixing it, but I think I will just contact OnePlus customer support first.
I'll be back later with my results.

arkasa said:
I gave this a try, but booting up after step 3 I still had the same problem. If I understand this method correctly, I think it is essentially the same as the other full restore methods I tried.
I think I may have found the problem though. I was looking at OnePlus' guide to installing OxygenOS. In it they said, "do not try to flash this build through TWRP. You will most likely lose your radio and IMEI which means a trip to our customer support." At this point I have repeatedly reset/restored my modem/radio so I don't think that is the problem, but I haven't seen anything about IMEI before. The IMEI is apparently stored in the EFS partition which as far as I can tell, is not touched by any of the restore methods I have tried. I took a look at my IMEI (about phone -> status) and it turns out my IMEI SV is 00. It's supposed to be a 16 digit number. I found a guide to fixing it, but I think I will just contact OnePlus customer support first.
I'll be back later with my results.
Click to expand...
Click to collapse
Are you flashing each of the extracted .img files from fastboot, exactly like the guide shows, or are you doing something else?

ryanmat said:
Are you flashing each of the extracted .img files from fastboot, exactly like the guide shows, or are you doing something else?
Click to expand...
Click to collapse
Yep, I ran each command listed in the guide and my phone was definitely in fastboot. Each command had a collections of "OKAY"s and ended with a "finished", which I assume means it executed as expected.

I have tried 2 different sim cards in my OPO (of two different companies, one of them as mine), and mobile data worked perfectly. Is it possible that my phone is ok and the problem happened in the sim card?
AND... my IMEI SV is 00 too. please update here if it has a connection.
Thank you !

omersa99 said:
I have tried 2 different sim cards in my OPO (of two different companies, one of them as mine), and mobile data worked perfectly. Is it possible that my phone is ok and the problem happened in the sim card?
AND... my IMEI SV is 00 too. please update here if it has a connection.
Thank you !
Click to expand...
Click to collapse
I'm not entirely sure what you're saying. Did it not work with the first SIM card, but it worked with the second?

Mobile data problem was occured (to me), after I rooted my OPO and tried to flash a new rom.
I still can't understand how it convinced my sim card, but the fact is that I tried two (to be sure) other sim cards which are not mine, and mobile data worked well.
When I returned my original sim card, problem started again.
So I am almost sure that sim card has a connection, but can't understand why. And why it happend precisely now, cause it worked well over two years.

omersa99 said:
Mobile data problem was occured (to me), after I rooted my OPO and tried to flash a new rom.
I still can't understand how it convinced my sim card, but the fact is that I tried two (to be sure) other sim cards which are not mine, and mobile data worked well.
When I returned my original sim card, problem started again.
So I am almost sure that sim card has a connection, but can't understand why. And why it happend precisely now, cause it worked well over two years.
Click to expand...
Click to collapse
sorry to intrude...but looks like mine problem too...but no connection with provider at all...and it worked 1 month normal (stock opo)..
could u flash the modem to resolve this problem?
jpvr
http://forum.xda-developers.com/one...e-plus-one-t3030545/post65841063#post65841063

Why don't you flash twrp flashable modem?
If your network is present but no data , mostly data service problem. Are you pay your mobile bills ?
Are you activate data services ?
Try this
https://www.androidfilehost.com/?w=files&flid=28032

drmuruga said:
Why don't you flash twrp flashable modem?
If your network is present but no data , mostly data service problem. Are you pay your mobile bills ?
Are you activate data services ?
Try this
https://forums.oneplus.net/threads/cos-12-master-fix-thread.307446/
Click to expand...
Click to collapse
...yes i paid my bills ..
- my network connection to provider is dead...it worked perfecly for 1 month out of the box (see original posting for detailed action i took) this thread is about lack of data connection...but also MODEM related???
- tried the brand new simcard in my old Samsung sII... works perfetly, network connection with provider, data connection and calling..so no simcard problem

Long shot. Change any APN settings from IPv6 to IPv4. That was my problem when I had text/voice but no data.

I made a post on this and then called att gophone, due to seeing other sims working on this thread, and he helped me to fix. Posting my fix here in case others with isue find this post instead of mine.
Turned off wifi.
Turned off cellular data.
Went to APN and changed the apn (ATT Go Phone) from pta to nxtgenphone.
Turned on cellular data.
Finally had H+ above he signal bar, but had an X inside the bar.
Don't know if he did anything on his end, but the X went away after a couple of minutes.
Data was working, albeit kinda slow.
Turned off phone for three minutes per ATT rep.
Rebooted.
Data still slow, but it is at least working. Thinking I need to flash different modem. Battery usage has been higher the last day or two since I flashed c7 anyways.