Well, I'm busy 'cause I have to search for a stable wall before this problem becomes a nightmare...
Really, I have not the foggiest idea, why this simple tweak will not work for you. I think CeRegEditor is one of the best apps.
Could it be that there is a connection with your dual-sim-thing? Or is there one thing failed to notice in the constellation of your device? Or is the point that your taskbar is named "...test..."?
Ultimately it will will be the best you take my preferred variant 2 - so could all components proper work together...
but not to forget: you have sdkcerts.cab installed?