How to google unlock a z855 - Google Cell Phones

If you mean to unlock it`s google account or ID then you have to hard reset it. Which removes all it`s data & setting; return to it`s factory settings. Below is the steps to do that :

1. Begin with the device turned off.
2. First, press and hold just the Power key for 1-2 seconds, then quickly press and hold the Volume Up key as well.
3. Continue to hold both buttons until the Select Boot Mode screen displays.
   
4. Press Volume Up to cycle through the options and point to Recovery Mode.
5. Press Volume Down to select. If Volume Down doesn't work by itself, press Volume Down and Volume Up together to select.
6. After a few seconds, an android laying down with a yellow triangle will appear.
   
7. Press and release the Volume Up and Power keys at the same time.
8. Android system recovery will appear.
   
9. Press Volume Down repeatedly until wipe data/factory reset is highlighted.
10. Press the Power key to select.
11. Press Volume Down repeatedly until Yes -- delete all user data is highlighted.
12. Press the Power key to select.
13. Once complete, press the Power key to select reboot system now.

Get the network unlock code for ZTE z855
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Unlock ZTE Z855 How to Unlock ZTE Z855