Unlocking Bootloader Revvl 4 plus 5062z

I have tried to follow the instructions from the link https://highonandroid.com/android-root-101/how-to-unlock-bootloader-on-any-android-android-root-101-1/ to unlock the bootloader. It fails with the following error.

C:\Users\S\Downloads\fastboot>adb reboot bootloader

  • daemon not running; starting now at tcp:5037
  • daemon started successfully
    error: device unauthorized.
    This adb server’s $ADB_VENDOR_KEYS is not set
    Try ‘adb kill-server’ if that seems wrong.
    Otherwise check for a confirmation dialog on your device.

Any thoughts or help please would be appreciated.


At https://stackoverflow.com/questions/31638582/android-adb-devices-unauthorized there are many answers. Couple of them are not very complicated and worth a try:)
Welcome to the forum!

First is straight forward:

  1. Try Revoke USB DEBUGGING Authorization.
  2. Enable USB debugging again.

The other that pops out is:

In sequence:

    adb kill-server
  • in your DEVICE SETUP, go to developer-options end disable usb-debugging
  • press REVOKE USB debugging authorizations, click OK
  • enable usb-debugging
adb start-server

You should get a window on your phone saying always slow from this device that’s why it’s unuatherized

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