If you try to run commands like fastboot flash boot , fastboot flash recovery , or fastboot flash system while in this state, the bootloader rejects the write request, triggering this error. Prerequisites Before Unlocking
Once you've confirmed your device is in fastboot mode and recognized, run the following command: fastboot flashing unlock [10†L5-L7]. A confirmation screen will usually appear on your device. Use the volume keys to navigate and the power button to confirm the unlock.
The error message is a security safety measure triggered by Android’s Android Open Source Project Bootloader when you attempt to flash firmware, custom recoveries (like TWRP), or system images via Fastboot while the device's bootloader is still locked. To bypass this restriction and flash your files successfully, you must toggle the software permissions inside your phone's operating system and execute the proper unlocking commands through the computer console. Understanding the Error: What is the Flashing Lock Flag? If you try to run commands like fastboot
When this flag is "locked," the bootloader will reject any attempts to write new data to system partitions, protecting the device from potentially malicious or unstable software. You'll likely encounter it after using commands like fastboot flash recovery recovery.img [9†L7-L9].
: Be aware that unlocking the bootloader will erase all user data on the device as a security measure. Flash with Fastboot - Android Open Source Project Use the volume keys to navigate and the
python mtk.py unlock
Lock and unlock the bootloader | Android Open Source Project Understanding the Error: What is the Flashing Lock Flag
A concise report describing the occurrence, root causes, diagnostic steps, and recommended remediation for the error message: "failed -remote 39 - flashing lock flag is locked. please unlock it first 39--".
Before you can run a terminal command to unlock the device, you must give the device permission from within the settings menu.
One highly specific and confusing error that users encounter while using Fastboot is: FAILED (remote: '39-flashing lock flag is locked. please unlock it first 39--')