STM32MP257F-DK: Critical PMIC (STPMIC2) regulators disabled and locked (Write failed / Permission denied)
- March 14, 2026
- 3 replies
- 278 views
I am working with the STM32MP257F-DK using the official Starter Package. Suddenly, the board entered a state where several power rails are disabled. The ST-LINK LED (LD5) is blinking red slowly, and there is no HDMI output (0V on the rail)
I have SSH access via USB OTG (usb0), but the system is in a "degraded" state.
The ST-LINK is not recognized by the PC.
HDMI monitor detects no signal.
Diagnostic Data (Output of grep "" /sys/class/regulator/*/state): I have attached a screenshot, but here are the critical regulators currently in disabled state:
regulator.11 (vdd3v3_usb) -> disabled
regulator.12 (v5v_hdmi) -> disabled
regulator.3 (vddio3) & regulator.4 (vddio4) -> disabled
regulator.7 (vddcore) -> disabled (Surprisingly, since the CPU is running).
Attempts to fix:
Tried to enable them via sysfs: echo enabled > /sys/class/regulator/regulator.12/state -> Result: Permission denied.
Tried to force it via I2C: i2cset -f -y 0 0x33 0x93 0x01 -> Result: Write failed.
Booting in DFU mode (000): The board is not recognized by STM32CubeProgrammer (Invalid USB port name), possibly because the USB/ST-LINK rail is down.
Question: Is the STPMIC2 in a permanent hardware protection lock? How can I force a factory reset of the PMIC registers if the Secure OS (OP-TEE) or the Kernel has locked the I2C writes? Could this be a Device Tree misconfiguration in the Starter Package?
