Symmetrize Uv Util
Does this addon work with multiple UV map channels?
No, only the active UV map is modified by this add-on.
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.
Can I adjust the position of the mirror axis?
Yes, you can now move the symmetric axis freely by putting the 2D cursor.