1. First make sure you are running Lollipop 5.0.2 Build 14.5.A.0.242 / 14.5.A.0.270. Go to Settings > About to verify this. The below screenshot is of C6902 but the method will work on all models of Z1 running Build 14.5.A.0.242 / 14.5.A.0.270.
2. Download KingRoot v4.1.0 and install it in your mobile :- "d-h.st/34c1"
3. Open the KingRoot app from your mobile , Click on Start Root , the Rooting Process will start. ( You need to connected to internet via WiFi or Mobile data )
THATS IT YOUR PHONE IS NOW ROOTED
To Replace KingUser with SuperUser follow the steps :
1. Download the file - Replace_Kinguser_with_SuperSU LINK :- "d-h.st/ZxN8"
2. Extract the file and copy the mrw folder to the root of your internal storage.
3. Download Terminal Emulator for Android from PlayStore :- "play.google.com/store/apps/details?id=jakpal.androidterm&hl=en"
4. Open the Terminal app in your mobile , enter the command " su " ( without quotes ) . Allow Root Access in your mobile.
5. Now run the command - " sh /sdcard/mrw/root.sh " ( without quotes )
6. The SuperSu app will launch automatically , it will ask to update binary , click on CONTINUE , then Select NORMAL method. After the Binary is installed it will ask to reboot your device.
Note : This method works on both locked and unlocked bootloader devices!!!
Note :- To download Kingroot , Replace_Kinguser_with_SuperSU LINK, Terminal Emulator links are underlined. To download copy the underlined link and open in a new browser tab
Note : - I am not responsible for brick your devices.