Wait for the LED to blink, then power off, remove the card, and restart the PLC. The password and program will be cleared. Firmware Update Method :

While "unlock services" exist, they are rarely magic. They carry the risk of data loss, malware infection, and legal liability. The best "unlock" is a well-documented project handover. If you are currently staring at a locked PLC, weigh the cost of a hack against the cost of starting fresh—sometimes the clean slate is the safer investment.

Instead of locking the whole project, only apply protection to necessary FBs/FCs. Conclusion

Method 1: The Top Industry Solution (The Blank SIMATIC Memory Card Trick)

Using unofficial unlocking methods may void your Siemens warranty and support agreements. Siemens explicitly warns against using unauthorized tools and methods.