Cellular data not working, ONLY through hotspot

[Dr.Kvak]

Hi,
I've got iPhone 4S, ios 8.4.1

my problem:
If I turn on the cellular data, than in any application on my iPhone I get the message "Could not activate cellular data network." (and I can't access the internet)
BUT if I turn on the hotspot, the connected wifi device can then access the internet (thru my phone!) and in Settings I can then see amount of data transfered.

Details:
- I tried reseting network configuration, no success.
- This device was restored from an older backup (of iPh2G) and it is possible, that in the time of creating the backup, there was an "Disable 3G/EDGE" profile activated on my (previous) phone. And here comes another strange thing - when I open "Profiles" in Settings, there appears to be none, but when I attemp to install a new APN setting it says "there cannt be more than one APN profile installed!"
- This is my first attempt to connect to the internet with this phone.


Any ideas please?

 

[chevelleguy3]

Try a restore as new and see if that fixes the issue. If that doesn't work, it could be a hardware failure.

 

[Dr.Kvak]

Well because of the fact, that iPhone is obviously capable of connecting (hotspot thing) it seems improbable to me that it could be a hardware issue...
Complete restore is surely worth trying but (because of understandable reasons) I thought about it as of the last option...

 

[chevelleguy3]

I wouldn't rule out hardware failure based on that. I've seen them do some crazy things and it be the logic board failing.

 

[Dr.Kvak]

Ok, thanks. If there won't be any other suggestions soon, I will try the complete restore...

 

[Dr.Kvak]

I got it!

There really was an old configuration (from my old backup) that was still active! BUT NOT VISIBLE OR REPLACEABLE anywhere on iPhone!
Even though Apple stopped using this profile format a long time ago, it was transfered with backup, activated, but not displayed anywhere in settings and it was impossible to replace it with new APN settings!

So by an absolutely legal way I got my iPhone into non-working state!


Anyway what I did>

How to delete old APN (or simmilar) settings from iPhone
I found out that when you create a backup of your phone (via iTunes), you can then explore the backup with something like iBot and modify it.
You have to delete APN settings in file "com.apple.managedCarrier.plist".
and any records with the same values (asi in managedCarrier.plist) and any links to them in file "preferences.plist" in part NetworkServices.
Then upload your (modified) backup to your phone, reboot and it should work.
Good luck, contact me if necessary.