a post like this is very dangerious coz any one write anything and a newbies how don't pay attention will kill his phone for sure !!!!!!
for k750 read this :
-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 !!!)
this is for the health of your phone, if you are not carefull i will read your post in : help me my phone is dead section :D