Some faces are not moving with the armature

I’ve paid for and downloaded (can of worms I know) a rigged model which I am transforming into a slightly different character. I’ve used booleans to cut a hole in Ichigo’s hood, but the faces I cut are not transforming with the model.

I can’t see any weight painting, the model is just flat blue weight, except for the hood, which is orange for some reason. Needless to say I don’t understand what’s going on.

.blend:
http://pasteall.org/blend/index.php?id=52990

When you cut the hole, did it add vertices onto the mesh? If it added vertices, they are not rigged or assigned to any bone. It also messed up your uvmap. If all you did was delete vertices, it should be fine. You can also delete faces and it will be ok. But if you add, you have to assign those to the bones. And also might have to fix your uvmap.

Yeah you will have to assign them to the vertice group.

Maybe this tutorial can help.

Yes it did add vertices, and I selected them and assigned them to the right bone. Thanks