Kis Maike Carvalho
Have you tried vol up + vol down + power all together at the same time?
I tried it before. My Nubia Z7 max had no answer, no chance to charge. That combination for 10-20 seconds rebooted my mobile.
My problem is really difficult to solve. I've tried holding the buttons vol up + vol down + power. No use. I tried to use this tuto: http: / / www.htcmania.com/showthread.php?t=843119. I can not insert a new port in QPST. Guess I'll have to give up, unfortunately stick with that brick. Could someone please help me?
If you can not get in Android, you should first check if you can get inside the recovery.
To get inside the recovery, switch the phone off keeping the power button pressed for 10 seconds, then switch it on pressing power button + volume up until the phone vibrates and the monitor turns on displaying the nubia logo.
If you can not get inside the recovery, then you have to boot to the bootloader. This mode is not something like the recovery or android, you get a screen permanently displaying the nubia logo and you can operate your phone using a computer.
To get inside the bootloader (fastboot) switch the phone off pressing the power button for 10 seconds, then power it on pressing power button + volume down until the phone displays the nubia logo.
At this point you should connect the phone to your PC and proceed with flashing a recovery image.
For more information about this process, please follow these steps.
If you can not get inside the fastboot menu, I am sorry but I can not help you.