Ensure your P'9983 has at least 50% battery charge . If the phone dies mid-flash, it could permanently brick the hardware.
OS 10.3.3.3216 (available only via autoloader). Common Reliable Build: OS 10.3.3.2049. Where to Download Autoloaders blackberry p9983 autoloader download
Moving to a specific OS version for performance or compatibility reasons. Ensure your P'9983 has at least 50% battery charge