The most trusted source for official, untouched BlackBerry OS autoloaders is BlackBerry Empire (formerly BerryRepair).
Direct link to the 9900 section:
➡️ https://blackberryempire.com/category/blackberry-9900-dakota/
Some specific links for the BlackBerry 9900 autoloader: blackberry 9900 autoloader link
Wipe Device: Click "Wipe Device" in BBSAK to clear the current OS (this will cause an "Error 507" on the phone, which is normal). 🔗 Reliable Download Link The most trusted source
Below is a comprehensive guide on finding the software, preparing your PC, and unbricking your device. 🛠️ What is a BlackBerry 9900 Autoloader? Post-Flash: The 9900 will reboot with a clean OS