The most effective way to remove the lock is by "confusing" the security system through a firmware downgrade to a version that did not support Anti-Theft, then upgrading back.
How it works (technical components)
No legitimate "anti theft removal firmware" exists because BlackBerry designed the device to be a brick. All current methods exploit the fact the server is offline—they are graceful hacks, not features. blackberry classic anti theft removal firmware
If you own a locked BlackBerry Classic today, you have two choices: The most effective way to remove the lock
BlackBerry Anti-Theft Protection operates similarly to Apple's iCloud Activation Lock. When a device is factory reset without logging out of the linked BBID first, the phone flags itself as untrusted upon reboot. If you own a locked BlackBerry Classic today,
For a permanent removal, you must flash an older firmware that does not have the updated anti-theft locks.
Note this number down; you will need it to download the correct autoloader file. 💾 Step 2: Download the Required Files and Drivers