Hello German folks :-)

[Martin1977]

0

I know it is just small difference and I decided to leave my Lumia 950 as it is now. With 059X4V9 firmware. It works with our LTE signals and it is the most important thing now :-)

here is my description, how I changed my RM-1105 to RM-1104:

00. Go to Setting -> Windows Update -> For Developers and turn Developer's mode ON, turn both options under Developer's mode ON
01. Connect phone to the computer using a USB cable
02. Download and unpack the AT&T_RM1104_RM1105_Softwarepack. To do this, create the "test" folder in the C: drive. Save the software pack in this folder and double-click it. The software pack is self-extracting.
03. Install the Windows Device Recovery Tool (part of the AT&T_RM1104_RM1105_Softwarepack in folder 006)
04. In the shell (command line), press the Windows key and enter CMD in the window that opens, and then press Enter
05. Enter the following command: cd c:\program files (x86)\microsoft care suite\windows device recovery tool
06. Enter the following command: thor2 -mode uefiflash -ffufile "C:\test\001\RM1105_1078.0017.10586.13053.12716.02FBB4_retail_prod_signed.ffu" -do_full_nvi_update -do_factory_reset
Note: It may happen that thor2 collapses during this process. In this case just wait until the phone has rebooted and re-run the process.
07. Wait until the transfer and flash operation has been finished. (Screen of the phone turns green, operation is finished on PC)
08. Enter the following command: thor2 -mode rnd -bootnormalmode
09. Start Your phone, don't connect to Wi-Fi and just turn Developer's mode on (the same way as point 00.)
10. In the shell, type the following command: cd c:\test\002 This will take you to the folder where the iuTool is stored.
11. In the shell, type the following command: iutool -p C:\test\003 -V
Note1: If error 0x80070490 appears, then remove the phone in the device overview and repeat point 10.
Note2: I needed manualy restart my phone after successfull instalation of all three CAB files. After that, computer also finished instalation task with message "Command executed successfully".
The data is now transferred to the phone. The following information should be displayed on the computer:
[1] Started device ** individual numbers - combination **
[1] Transferring files started
[1] Transferred file 1/3
[1] Transferred file 2/3
[1] Transferred file 3/3
[1] Transferring files complete: 3 files
[1] Update started
[1] Installation failed (HRESULT = 0x8024a110)
[1] Failed (0x8024a110)

ERROR: 0x8024a110
Note1: The error message can be ignored because the platform ID is changed here.
Note2: I didn't get any error message in my case. I just needed manualy restart my phone to get "update successfull" message
12. The phone restarts, the update is installed.
13. Enter the following command: cd c:\program files (x86)\microsoft care suite\windows device recovery tool
14. Enter the following command: thor2 -mode uefiflash -ffufile "C:\test\004\RM1104_1078.0017.10586.13053.11210.02FA05_retail_prod_signed.ffu" -do_full_nvi_update -do_factory_reset
15. Enter the following command: thor2 -mode uefiflash -ffufile "C:\test\005\RM1104_1078.0053.10586.13169.11210.035241_retail_prod_signed.ffu" -do_full_nvi_update -do_factory_reset
16. Enter the following command: thor2 -mode uefiflash -ffufile "RM1104_neu.ffu" -productcodeupdate 059X4V9 -skip_flash
17. Enter the following command: thor2 -mode rnd -bootnormalmode
18. Your Lumia 950 AT&T RM-1105 should restart now as unbranded Lumia 950 RM-1104
This procedure worked on my Windows 10 64bit computer without any problem.
Thank You CTHTC and TUV1 moderators of WPVision.de forum for providing me help and all the needed files to successfully perform change of my branded US AT&T Lumia 950 into unbranded EU Lumia 950.
best regards
Martin