Which are you using (e.g., Keil, STM32Cube, OpenOCD)?
Power cycle the board. The chip will now execute the safe, built-in bootloader.
Some microcontrollers have an independent watchdog that resets the chip if the firmware doesn't "feed" it frequently. When a debugger halts the CPU to write flash, the watchdog might not get fed, timing out and resetting the chip mid-programming, causing a corruption or lock condition. Disable the watchdog in your firmware during development, or hold the CPU in reset ( Connect Under Reset ) while initializing the flash programmer. writing flash programmer... fail unlock tool
Modern devices require a secure cryptographic handshake (Auth) before allowing a flash programmer to execute.
Determine if your phone uses a MediaTek (MTK), Qualcomm, or Spreadtrum (SPD) chip. Which are you using (e
Newer USB 3.0 or 3.1 ports often drop connections during low-level flashing. If your computer only has USB 3.0 ports, use a USB 2.0 legacy hub as an intermediary.
Before diving into complex troubleshooting, check these common pitfalls: Share public link
A damaged USB port or cable is corrupting the data stream.
I can give you more specific, detailed steps to fix this error. Share public link