Symmetrize Uv Util
Why do I get a wrong result?
Make sure your model is symmetry and the axis setting in our add-on is correct (See Documentation).
Also, make sure the 'UV Sync Selection' button in the UV Editor is turned off.

Does this addon work with multiple UV map channels?
No, only the active UV map is modified by this add-on.
Can I adjust the position of the mirror axis?
Yes, you can now move the symmetric axis freely by putting the 2D cursor.
What is "Open Wings"?
This feature has been removed in v1.6.0.
(This feature is similar to the Expand Mode except that the original UV map is scaled down to half size.)