you need a sercice cable and you must know your cid
-cid 36 use setool2 : you have here a tutorial.
-cid 49 = semctool 8.4 free ; look what firmware you have on your phone, first flash only main with K750_R1BC002_MAIN_EU_EMEA_CID49.mbn, unlock , and for finish flash the main that was one your phone (without FS and without FINALIZE !!!)
enjoy :)