Flashing rewrites the phone’s operating system. It bypasses the user lock entirely because you aren't “unlocking” the phone—you are reinstalling the software from scratch. This method works even if the phone is:
A standard flash file (firmware) might retain user settings. A properly prepared "without password" or "full flash" file erases the user data partition completely, removing the lock and resetting the security code to the factory default of 12345. Nokia C1-01 Flash File Without Password
A "Flash File" (or Stock ROM) is the operating system software specifically designed for your phone's hardware. For the Nokia C1-01, this is a .mcu, .ppm, and .cnt file package. Flashing rewrites the phone’s operating system
Flashing this file reinstalls the phone’s firmware, effectively wiping out viruses, fixing corrupt system files, and restoring the phone to its original factory state. A "Flash File" (or Stock ROM) is the