Use the original USB cable; some third-party cables don't support data transfer for fastboot.
If a thief steals a phone that has a locked bootloader, they cannot simply flash a new operating system to bypass the lock screen or user data encryption. The lock flag ensures that the only software that can run is the one the legitimate user had installed. This makes stolen phones significantly less valuable and harder to resell, acting as a deterrent against theft. flashing lock flag is locked
At first glance, the phrase sounds like redundant technical jargon—of course a lock flag is locked. However, in the world of firmware, microcontrollers, and memory protection, this error indicates a specific, critical state. It means your device is refusing to write new data to a flash memory chip because a safety mechanism (the lock flag) has been engaged and cannot be overridden. Use the original USB cable; some third-party cables
Added a 100nF capacitor to NRST and a 4.7k pull-up. Performed a power cycle (not just a software reset). The lock flag cleared on the next attempt. This makes stolen phones significantly less valuable and
The error message is a security status in Android devices indicating that the bootloader is currently preventing any unauthorized changes to the system's protected partitions.
Lock and unlock the bootloader | Android Open Source Project
If software methods fail, the lock flag might be physically stuck. You have two options: