Connect your phone directly to your workstation using an authentic OEM USB data cable.
This is the core of the problem. Modern devices include a —a security mechanism that prevents unauthorized writing to critical partitions (like boot , recovery , system , or vbmeta ). When this flag is locked , the bootloader rejects any fastboot flash commands. Connect your phone directly to your workstation using
Look through the text output for lines such as Device unlocked: true or unlocked: yes . Once you see that validation, you can safely re-run your original flashing command, and the remote: '39-flashing lock flag is locked' error will be entirely gone. When this flag is locked , the bootloader
| Cause | Explanation | |-------|-------------| | Door / cover open | A toner access door, paper jam release cover, or front cover is slightly open. | | Interlock flag stuck | A small plastic flag that presses a microswitch is broken or stuck in locked position. | | Paper jam | Device locks all moving parts; flag stays locked until jam cleared. | | Fuser or drum unit not fully seated | Removable units have lock flags that must click into place. | | Cause | Explanation | |-------|-------------| | Door
It is essentially a security mechanism designed to protect the device's bootloader from unauthorized modification.
To help narrow down the solution for your specific device, could you tell me: What is the exact of your phone?
Also, enable to allow the computer to send commands. 2. Enter Fastboot Mode