Apologies for the double post, but just found this: For those Lumia devices not getting 8.1.2 GDR 2 Option-->check-->About-->Insider App: If it says: Branch WPB_CXE-R1-->Then you will not get update. Only WPB_CXE-R2 will! If any of our keen members can translate German:
drwindows.de/content/6126/windows-10-preview-fuer-phones-brangt.windows.html
Now, how can we change our Windows Insider app (mine =R1)
to Branch WPB_CXE-R2 ?!?
Hi dude
A quick question does your phone received Official Denim update from AT&T?
If not i want you to do some things provided if you are okay with it
1) I want you to go back to official version via Windows Phone Recovery tool. Check if there are any official updates in the phone update.
If there are no updates install Windows insider app and check the update branch you are currently on in the about setting.
If it shows main branch then you may have chances for GDR2 installation.
2) Now since your phone is not on Denim. We will need to update the current OS version to Denim (only OS no Firmware) via Preview for Developers App. Download the app and enroll and check for any updates in the phone update. Install the updates and after that unenroll in the PFD app.
Now check the update branch you are currently on which will change to another branch.
3) Now the major step after unenrolling from the preview for developers app..Open the Insider Preview app and check for any preview builds..If it shows only fast ring to you then are good to go.
Finally i want to say one thing all the process described above was a pure speculation on my end. Do this only if you intended to try.
Note : Report the branch status to me in each step for clarification on my end.
Good luck and notify me about the status on your end