Can't restore 1520

[Memristor]

I'm trying to restore a 1520 from a backup that was created on a 1020. It's not working and I can't explain why.
When I restored a back up from a 920 to the 1020 it worked flawless.
So here is more information maybe someone has experienced the same problem.

Lumia 920 with firmware Black and WP8.1 to Lumia 1020 with Black and WP8.1 works.
Lumia 1020 with Black and WP 8.1 UP 1 to Lumia 1520 with Cyan and WP8.1 does not work, backup doesn't show up, but the old backup from the 920 shows up.

Do I have to upgrade the 1020 to cyan and downgrade to WP1 (w/o Update 1)?

FYI I don't want to run beta Update 1 on the 1520

 

[Memristor]

I spent last evening trying to figure this one out. The only way to restore a phone that was backed-up under Update 1 is to install Update 1 on the new device as well. In the past is was possible to restore from 8.0 to 8.1 but once Update 1 is applied that doesn't work anymore.