A "flash file" or "PAC file" for the Nokia TA-1304 (a Nokia model identifier) is firmware packaged for device flashing — contains system image, radio/modem, bootloader pieces, and sometimes device-specific configuration. It's used to restore, update, or unbrick the phone.
: Restores the device if it is stuck on the Nokia logo or restarting continuously. Unlocking/Resetting nokia ta1304 flash file pac file