Failed -remote 39-flashing Lock Flag Is Locked. Please Unlock It First 39-- [exclusive] Jun 2026

Samsung uses a different mechanism called and KG (Knowledge Guardian) State .

For MediaTek and Spreadtrum (Unisoc) devices, replacing the bootloader with an engineering version can bypass the lock flag check.

Unlocking will perform a factory data reset and wipe all personal data from the device. Enable OEM Unlocking On your device, go to Settings > About phone Build number 7 times to enable Developer Options Navigate to Settings > System > Developer options and toggle on OEM unlocking USB debugging Reboot to Bootloader Connect your phone to a computer and run adb reboot bootloader

MediaTek chips often store the lock flag in the or bootloader partition. The error remote 39 is very common here.

If the toggle is unclickable, connect to Wi-Fi. If it stays grey, your carrier may have permanently locked the bootloader (common with Verizon or AT&T models). Samsung uses a different mechanism called and KG

: If you are trying to flash low-level files like the bootloader itself, you may also need to run: fastboot flashing unlock_critical Important Troubleshooting

If your device still boots normally into its stock Android operating system, you must toggle the software allowance switch first. Disconnect your device from the computer.

(Use unlock_critical to unlock bootloader and flash-critical partitions like xbl , abl .)

This is the prerequisite for any advanced modification. To enable Developer Options, go to Settings > About Phone and tap the Build Number seven times until a message says "You are now a developer!" [11†L9][12†L4-L5]. Enable OEM Unlocking On your device, go to

You are most likely to see this error in the following situations:

Use the volume keys to highlight "Yes" and press the power button to confirm. Reboot: fastboot reboot Method 2: Xiaomi/POCO/Redmi (Using Mi Unlock Tool)

: Certain hardware brands require a SIM card network handshake to authorize the OEM toggle. Ensure your phone has active cellular data enabled if the selection remains grayed out. Phase 2: Resolving the Lock Flag via Command Line

This error typically happens when a script or automated flashing tool attempts to write to sensitive system partitions while the critical hardware "lock flag" remains engaged. Below is a comprehensive guide to understanding why this happens and how to systematically resolve it. Why Does This Error Occur? If it stays grey, your carrier may have

Open a terminal (Command Prompt/PowerShell) on your PC in your Platform Tools folder adb reboot bootloader

If your device is locked to a specific carrier (like Verizon or T-Mobile in the US), unlocking the bootloader might be impossible. Carriers often disable the "OEM Unlocking" option. In such cases, your only recourse is to contact your carrier to request a SIM unlock or, if possible, to ask about their bootloader unlocking policy [12†L12-L15].

: Go to Settings > About Phone and tap on Build Number seven times until it says "You are now a developer."

: Open your device's primary Settings app, choose About Phone , and locate the Build Number . Tap this entry rapidly 7 times until an on-screen notification confirms that Developer Options are unlocked.