Samsung uses a different mechanism called and KG (Knowledge Guardian) State .
Once the device reboots (or you manually boot back into fastboot), verify that the lock flag is gone by typing: fastboot getvar unlocked
If you are using a specific flashing tool (like SPD Upgrade Tool or a specialized ROM flasher), ensure the device is connected in the correct state and the necessary drivers are installed.
Remove and reinstall each removable unit. A misseated unit keeps the lock flag active.
your device and erase all data. Confirm the action on the device screen using the volume buttons and power key. Android Open Source Project Step 4: Verify Unlock Status
Manufacturers implement the flashing lock flag for several reasons: