Check the SHA-256 hash if provided. Corrupt files will permanently brick your device.
: Some users have found success by installing an older 10.3.1 Autoloader (if the device permits) which did not have the same anti-theft enforcement, allowing you to sign in with a new ID. Note: 10.3.3 often blocks downgrading to 10.3.2 or earlier via NVRAM. Where to Download download blackberry anti theft removal firmware 10.3 3