some form of degrading i605 4.4.2 or repair imei?

a way to make the downgrade to 4.4.2 i605 in vercion or perform the repair imei since mine has it null and tried cdma workshop , nv writter .etc and all throw the same error no response from the device gets as:(

from xda-developers http://ift.tt/25q0KA4
via IFTTT