Google's built-in security can also trigger flashing blocks. If a device is reset improperly, FRP locks the partitions until the original owner's account credentials are verified. Step-by-Step Guide to Resolve the Error
Dismiss Got it. On this page. Get into the bootloader. Unlock the bootloader. Lock the bootloader. Set lock and unlock properties. Android Open Source Project Fix Device State Locked Unlockable in Fastboot Mode
Here is a comprehensive guide explaining why this error happens and exactly how to fix it. What Does This Error Mean?
The error message occurs when you attempt to flash custom firmware, a custom recovery, or an OTA system update to an Android device while its system security mechanism restricts modifications. This security barrier is known as the bootloader lock . flashing lock flag is locked please unlock it first full
This error is rarely a bug; it is usually a security feature designed to save you from yourself—or from hackers.
Connect your device to a PC and use the command adb reboot bootloader or use a hardware key combination (usually Power + Volume Down) while the device is off. Run the Unlock Command: In your PC's terminal, type: fastboot flashing unlock (for newer devices). fastboot oem unlock (for older devices).
When you see this message, it means the device's bootloader is currently locked, which prevents the fastboot flash command from writing new data (like a custom recovery, boot image, or firmware) to your phone. Even if you have enabled "OEM Unlocking" in your developer settings, that action only permits the unlock—it does not actually perform the unlock itself. Google's built-in security can also trigger flashing blocks
This error occurs when you try to use a tool like "Mi Flash" to install new software (firmware) while the phone’s security "flag" is set to "Locked." What This Means
Only the manufacturer (the person with the original key) can change the furniture inside.
To resolve this error, you must first understand the security layers implemented on modern mobile devices. On this page
I can then provide step-by-step instructions for your situation.
Unlocking the bootloader has consequences: