[Guide] How to Load an OS Using Autoloader. - CrackBerry forums
Look for "Official OS" threads for the Bold 9900. Stable versions like OS 7.1.0.1047 are highly recommended. 3. Step-by-Step Flashing Guide Launch the Autoloader: Open the downloaded file on your PC. A command prompt window will appear. Prepare the Device: bb 9900 autoloader download
Official autoloaders are no longer hosted by BlackBerry. Reputable community sources include: [Guide] How to Load an OS Using Autoloader