Mine came off in one piece but was quite compressed and brittle, so I just smeared a small amount of silicone sealant on the gasket and stuck it back into place, then a small amount again on the other side of the gasket then the icv back on and bolts tightened, easy peasy, but as tours it still well attached is just bung a little sealant on the side you can get to and bobs your uncle
