[Jozef jurcisin]

When I am downloading Developer app to my windows phone 8 I am getting this error "developer account to download the preview you must be registered as a windows phone developer"

I have same problem with 3 Lumias 810 now! Can you help me please!
Last year I was able to so.
I was on windows 10 I went back to Windows 8 with WDRT.

[Jozef jurcisin]

I was able to bring my old Lumia's 810 from windows 8 to win 10 I am on 10.0.15063.297!

I did not get any help from MS support or Developers.com

here are my steps:

Now you can update to WP8.1GDR1 with Offline Update Packages. Push these packages from PART1 to PART4.
Lumia 810 was on 8.1 CIM card was not used no account was assigned. time was not correct
install 10586.107 first
use HARD RESET
Uninstall Extra & Info
email account was not assigned
install InteropTools_RC-1.9-pre10_arm_1.9.390.0 ( this ver worked best for me)
change phone to Lumia 640:

PhoneManufacturer = NOKIA
PhoneManufacturerModelName = RM-1072_1044
PhoneModelName = Lumia 640
I DID NOT USED this:PhoneHardwareVariant = RM-1072 my phone didn't have it this
go to update I got 10.014393.1066 after this update I got 10.0.15063.297
+ you can get Glance work too

https://forum.xda-developers.com/win...3527340/page25