[Guide] How to Load an OS Using Autoloader. - CrackBerry Forums
: If a newer update caused performance issues or "battery drain," an autoloader is the only way to return to an older, more stable version of BB10. Clean Slate blackberry stl100-2 autoloader
Search archive.org for “BlackBerry Z10 STL100-2 autoloader”. You will find community backups of Google Drive and MEGA folders. [Guide] How to Load an OS Using Autoloader