Ibo you can not replace just the CPU. The CPU is tied to to the nand memory with the serial number of the device, the modem, home button and the eeprom baseband memory on the i6 I would forget about your touch id! the CPU is only reworked for data recovery purposes due to the amount of work involved. If you can't live without it you would be better to replace the phone. There is a A8 sn programmer but it is not on the market yet.