My MP09-B has a broken knee right out of the box, I found a easy and secure way to fix it.
1) Glue the broken knee back. Don't forget to take out that little black rectangle box which caused all these issues.
2) Just cut a gasket using yogurt box, like my picture below. I choose yogurt box because it's easy to find, good quality, hard and very thin.
3) file the knees a little, prefer the same thickness as the gasket.
4) Glue the gasket with the injured knee.
5) Put it back. As you can see, the gasket is thin enough that it's hardly noticeable.
6) Now it's secure enough to transform without worry the knees. If you are not too sure, you can add another gasket at the other side of the knees, double insurance. For me, one is good enough.
