The BlackBerry Z3 (STJ1001) is a great test device because of its unique square screen ratio (540x960). But without the proper developer autoloader, it is just a brick.
The tool will automatically flash the OS and restart the device.
This preserves the existing radio firmware (useful if the device is SIM-unlocked or has a tuned cellular stack). A mismatched radio + OS can cause no cellular service.
Developers targeting this device must account for its hardware constraints to ensure app performance:
Another flag:
Once the developer autoloader is installed: