This will work using any of the four blocks as borders. But the pattern doesn't turn the corner; it stops and then starts again. This solution isn't elegant or clever; but it does work, sort of.
There are four different blocks that can be used to make borders; so there are 12 different border/corner possibilities. The results aren't much different from the first attempt, with one exception.
I would prefer a block that matched both ways.
This turns the corner and adds emphasis to the corner. Which is fine if that's what you want to do.
I would prefer the corner to be a continuation of the rest of the border.
This is better but the white star still places more emphasis on the corner than I want.
Finally the blue and the white are evenly balanced. The corner is part of the border and doesn't interrupt it.
This new corner block works equally well when any one of the other 3 original blocks are used for the border.
For more ideas for playing with an Empire Star block go to My Posts by Subject in the sidebar on the right and click on Empire Star.