Could be faulty fastboot driver. Did you use the latest version from Google platform tools? Try a different computer also and don't forget to install the drivers from Motorola also. Try a different cable too. Files inside the bootloader could be corrupted, to fix it try to reflash the newest firmware version of your variant, if you're already using the newest version reflash the firmware again. If the problem persists your variant could be using different commands or even be carrier locked or region locked, double check that.hi friend
I have the z3 play xt1929-6( software channel OPENMX) device does not unlock the bootloader I have allowed to unlock in the developer, I execute the command on the command prompt window
> fastboot oem get_unlock_data
(bootloader) Failed to get unlock data.
OKAY [0.019s]
Finished. Total time: 0.022s
Please let me know my device is having a problem and how to unlock the bootloader, thanks
Hidden commands can be found here but it's the last possible move. Try talking to other people who have the same variant, it could be a variant specific commands not documented. Good luck