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Failed -remote 39-flashing Lock Flag Is Locked. Please Unlock It First 39-- Jun 2026
Before the device will accept an unlock command in Fastboot mode, you must authorize it from within the Android operating system. Navigate to .
: Check the current lock status by running: fastboot getvar all or fastboot flashing get_unlock_ability
# First, try to read the flash to see if it's accessible at all sudo flashrom -p <your_programmer> -r backup.bin
fastboot oem unlock UNLOCK_CODE
On the left-hand menu, click on the "Option Bytes" tab (represented by a memory chip icon).
To comprehensively cover this topic, I need to gather information from multiple angles. I will search for the exact error message, related tools, underlying technologies (SPI flash, lock bits), and solutions. I will also look for community discussions. search results show several relevant threads. I need to open them to gather details. search results show the error is common in Android bootloader unlocking (fastboot) and in embedded systems (SPI flash, flashrom). The article needs to explain the error, its causes, and solutions. I will structure it as a long-form article with an introduction, explanations of the error in different contexts, root causes, solutions, troubleshooting tips, and best practices. I will cite relevant sources. comprehensive guide will explore the frustrating error message you may encounter when programming devices: "failed -remote 39-flashing lock flag is locked. please unlock it first" . We will decode what this message means, why it appears, and provide detailed, actionable steps to resolve it and get your device working correctly.
If you’re technical and the device is off, locate the interlock flag (plastic tab near microswitch). Gently move it to see if it springs back. If broken, needs service. Before the device will accept an unlock command
Open a terminal or command prompt in your Android Platform Tools folder. Run the command: adb reboot bootloader .
: The device security flag is preventing any modification to the system partitions. This is a safety feature to prevent unauthorized software (like malware or unverified firmware) from being installed.
This essentially bricked my update process. No matter what I tried—restarting, reconnecting, or using different tools—the system refused to proceed because of a persistent “flashing lock flag.” The error message itself is cryptic for most users, and the solution isn’t obvious. You have to dig into low-level commands or proprietary unlock tools just to clear a flag that shouldn’t be locked in the first place. To comprehensively cover this topic, I need to
At the deepest software level, a bug in the flashing program or the device's bootloader can itself trigger this error. A documented example in U-Boot (a common bootloader) was a when trying to call flash lock methods on SPI NOR flashes that didn't properly support them. This could cause the bootloader to crash or behave unpredictably, generating this lock-related error as a consequence.
Go back to the main Settings menu and navigate to . Find OEM Unlocking and toggle it ON . Find USB Debugging and toggle it ON . Step 2: Boot into Fastboot Mode
The error indicates a failure in the communication between your debugger (e.g., ST-Link) and the microcontroller. Specifically, the microcontroller's internal logic has flagged that the memory is restricted. search results show several relevant threads
Possibilities: