If you bought the device secondhand, submit a Dell Ownership Transfer form online first. Once the asset is registered to your name, Dell support can legally generate the dynamic master unlock code.
While codes vary by individual Service Tag, some users have reported success with specific strings or patterns. You can try the following widely cited code: 8BxRmM02IiZp01X1 : After typing the code, you must hold the key and press twice [10]. Note that the characters in this code are , not the letter "O" [10]. 2. Official Dell Support (Recommended)