Lock and unlock the bootloader | Android Open Source Project
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 Flashing Unlock is Not Allowed
Verify that the "KG State" or "RMM State" in the top left corner of Download Mode changes from "Checking" or "Locked" to "Prenormal" or disappears entirely before trying to flash via Odin. Troubleshooting Common Failures
In essence, this error means:
If you are a developer, Android enthusiast, or someone trying to flash custom firmware on a mobile device, seeing the error message can be frustrating. This error typically appears in the terminal or command prompt when using fastboot commands, signaling that the bootloader—the gatekeeper of your phone's operating system—is locked and won't allow unauthorized modifications.
Go to and find the Build Number (or MIUI version/Software version).
Unlocking the bootloader will wipe all data on your phone. Back up first if possible. flashing lock flag is locked please unlock it first full
If the OEM Unlocking toggle is greyed out in your settings, your device might have an unyielding carrier lock (common on US carriers like Verizon or AT&T). You must request a carrier unlock before you can toggle this switch.
Sometimes, even after running fastboot flashing unlock , you might still see "flashing unlock is not allowed" or "flashing lock flag is locked" when trying to flash specific critical partitions. This is because the "critical" unlocking needs a separate step. Ensure you have already done fastboot flashing unlock .
(If you see your device's serial number, you are ready to proceed.) Run the universal unlock command: fastboot flashing unlock Use code with caution. Lock and unlock the bootloader | Android Open
If you’re seeing the error message you are likely dealing with an Android device (often a Xiaomi, Redmi, or Poco) that has a locked bootloader .
Android devices ship with a locked bootloader to protect user data and prevent malicious software from changing the operating system. When you use commands like fastboot flash or fastboot flashing unlock critical , the system queries an internal security variable. If this variable returns a zero value, the partition engine throws a hard stop error to safeguard the phone. This roadblock occurs under two primary circumstances: