ST STM32L4 Option Bytes Unlock

The option bytes of the STM32L4 series of devices can be reset to default values. SEGGER implemented support for these features via a dedicated utility called Device Provisioner. For more information about this, please refer to the Device Provisioner article. STM32L4 Option Bytes Reset features are implemented in the PCode_DevPro_ST_STM32L4.pex script file.

Usage

DevPro -operation [operation_name] -if SWD -speed 4000 [-SetConfigVal parameter_name=value] -ScriptFile PCode_DevPro_ST_STM32L4.pex

Operation	Parameters	Values	Description
PerformUnlock	-	-	Unlocks the device by resetting the option bytes to default values.

Examples

Option Byte Reset

Example

DevPro.exe -operation PerformUnlock -if SWD -speed 4000 -ScriptFile PCode_DevPro_ST_STM32L4.pex
SEGGER Device Provisioner V9.18
Compiled Feb 11 2026 16:31:11
Command line: -operation PerformUnlock -if SWD -speed 4000 -ScriptFile PCode_DevPro_ST_STM32L4.pex
Firmware: J-Link STLink V21 compiled Aug 12 2019 10:29:20
S/N: 773749541

J-Link log: DAP initialized successfully.
J-Link log: Reset target...
J-Link log: DAP initialized successfully.
J-Link log: Reset option bytes to factory settings...
J-Link log: Resetting FLASH_OPTR...
J-Link log: DAP initialized successfully.
J-Link log: Reset target...
J-Link log: DAP initialized successfully.
J-Link log: DAP initialized successfully.
J-Link log: Reset target...
J-Link log: DAP initialized successfully.
J-Link log: Resetting Write protection (WRP) and PCROP...
J-Link log: DAP initialized successfully.
J-Link log: Reset target...
J-Link log: DAP initialized successfully.
J-Link log: Option bytes reset successfully!