Unlocking a password usually follows one of two paths: (retrieving the original password) or Clearing (resetting the device to a state where no password is required). S7-300 MMC Password Recovery
, software usually provided a way to "clear" the CPU memory and reset the hardware password to factory defaults (e.g., using "CLEARPLC" as a password).
The S7-300 stores passwords on its , not just the CPU memory. S7-300 PLC Password Reset: Erase MMC Memory Card