[Q] Strange Galaxy S5 topic

Hi there! Some friend gave me a S5 and said it can't get signal, so it can't make or receive calls. At first sight I realized it has no IMEI and searched how to fix it and discovered the S5 has to be rooted. Well I downloaded CF-Auto root to make it but I got a big problem... When I make the secuence Vol - home button and power I get a factory setting menu in chinesse... I can't use ODIN at all...
How can I proceed to root and try to fix IMEI issue?
Model : SM-G900F

PS. I say it's strange because I think it's a fake S5