A device uses donor circuit blocks in a donor integrated circuit to replace defective circuit blocks in a recipient integrated circuit and create a functional integrated circuit. The recipient integrated circuit has a first number of cores, the first number including a recipient core, and the recipient core having a recipient circuit block, a switching element, and a recipient communication point, the first number of cores connected by a data bus. The recipient core has an intended function. The donor integrated circuit has a second number of cores, the second number smaller than the first number. The second number includes a donor core having a donor communication point electrically connected to a donor circuit block, the donor circuit block having the intended function. The recipient connection point is electrically connected to the donor connection point and the switching element switched to disable the recipient circuit block in the recipient core.