1.check under Settings/About Phone your Build number is not above S110, S111 and above will cause Boot loop
2.check the box under Settings/Security/Unknown Sources.
3.Download Farmaroot apk from XDA Developers Download Link Here.
4.install the Farmaroot.apk and accept all the security warnings then you will find Farmaroot in the Applications Menu.
5. Start the Farma root App and choose one of the root methods both will work
6. if your device is rooted you will get a success message
7.Now you need to restart your device to get Super su Rights app (this app is responsible for root rights and will pop up every time a program needs the root Rights and you can choose to give them or not.
8.now you need to download TWRP recovery from this link extract the zip file and put the recovery file on your sd card on root and not inside any folder the name must be (recovery.img)
9.download and install mobile uncle from play store or from this link to install the TWRP Recovery
10. before you start Mobile uncle app be sure that the device language is English and grant the Program root rights.
11.choose the Recovery Update option (if the recovery.img is in root of SD you will get this)
12.click on recovery.img and accept the recovery update
13.after recovery you will be asked to boot in TWRP Recovery accept with OK if you have a Custom rom on your device to install
15.choose wipe make a Factory Reset by swiping the blue point
16.click on install and choose the Custom rom zip file and install it
17.choose wipe cache/dalvik again and reboot the system
18.TWRP will ask you if you want to install Root, you can root like this or root later with Farmaroot.