For boards with a bunch of layers and BGA/LGA packages, that have internal manufacturing errors or damage (e.g from overflexing), repairs can be untenable.
If the parts all have pads on their perimeter, then a jumper wire can replace internal traces. If the pads are underneath the part, and the trace is only internal, than a jumper may not be feasible, unless the damage happens from the surface in, in which case each layer can be jumpered at the damage.
If the parts all have pads on their perimeter, then a jumper wire can replace internal traces. If the pads are underneath the part, and the trace is only internal, than a jumper may not be feasible, unless the damage happens from the surface in, in which case each layer can be jumpered at the damage.