I've made a tool for simple IMEI recovering.
Just download it, unpack, open run_automatic.bat and connect you phone.
If you will have any errors, try manual version run_manual.bat.
Your phone must be turned on and USB Debugging must be enabled (About phone -> Tap multiple times Build number; Developer Options -> USB Debugging)
Just follow the instruction. If you will have any problem or find a bug, post it here.
UPDATE: New version released as there was a problem for some guys. Now it also requiring ROOT.
UPDATE2: Some more changes
UPDATE3: Added manual version. Also if you have problem with automatic version, post here screenshot of error.
Download v1.3: https://mega.co.nz/#!yUIhDICD!EMgwlQdWcduzcdZy2-30H97mn9alK1uxxddI0LH0gMM