This is the ultimate guide put together to clear all those.
*Use Mozilla Firefox to get the unlock_bootloader image* Chrome isn't working due to bugs in site
Things you need:
1. ZUK Z2 (Z2131/Z2132) [Obviously]
2. "unlock bootlader.img" from developer.zuk.com
3. Minimal ADB and Fastboot from Here
4. Latest TWRP from Here
5. If you want to root download SuperSU from Here
6. MI Flash Tool from Here
Unlocking bootloader factory resets the device, so backup your files before hand.
Getting the Unlock Image:
This one thing is a big problem to attain for many users.
1. Head to developer.zuk.com (Use Chrome to translate the page)
2. Click Login and use the following details
Account doesn't work anymore, but you can easily create an account now.
(Login before heading to unlock page)
3 .Click Unlock at the top.
4. Click NEXT on Step 1.
5. Select Z2 from dropdown list.
6. Type in your Serial Number. (You can find it at Settings > About > Status > Serial Number)
If you have a 6 character serial number, add two zeros at end
If you have a 7 character serial number, add one zero at end
7. Give your email ID (Gmail works too)
8. Accept the conditions and click NEXT.
9. A Dialog Box opens up stating that you will recieve an email with the bootloader image.
10. Check your Inbox and Spam folders.
1. Install Minimal ADB and MI Flash (to ensure you get all drivers)
2. Place the "unlock_bootloader.img" in the fastboot installation folder.
3. Run following commands.
(a) adb devices [Your device should be listed, if not, check drivers]
(b) adb reboot bootloader
(c) fastboot -i 0x2b4c flash unlock unlock_bootloader.img
You should see this:
"target reported max download size of 1610612736 bytes
sending 'unlock' (0 KB)...
OKAY [ 0.037s]
OKAY [ 0.053s]
finished. total time: 0.090s"
(d) fastboot -i 0x2b4c oem unlock-go
You should see this:
"OKAY [ 0.041s]
finished. total time: 0.041s"
(e) fastboot reboot
4. You should end up with an unlocked bootloader.
1. Place TWRP downloaded from official site in the fastboot installation folder.
2. Run the following commands.
(a) adb reboot bootloader
(b) fastboot -i 0x2b4c flash recovery twrp.img
(c) fastboot reboot
3. You have successfully installed TWRP
Rooting using SuperSU.zip
1. Place the downloaded "SuperSU.zip" into the root folder of phone to. (That would be easy to find while installing)
2. Reboot to TWRP
3. Select Install and locate SuperSU.zip
4. Swipe to flash.
You should end up with a unlocked and rooted Z2.
Comment for flaws or if you want me to add more info at a specific step.
If you get a message saying "Daemon started succesfully" re-run the previous command.
Thanks to Balraj at zukfans.eu for Login Details
Hit thanks if this helped you.