Hi,
I am currently facing an issue where TrustZone cannot be disabled on the STM32U545 device with custom hardware.
1. [Part Number] STM32U545VET6 on custom hardware
2. [Environment] STM32CubeProgrammer 2.20.0 with ST-LINK V2; custom Zephyr application and custom TFM platform
3. [Schematics] PH3 (BOOT0) is connected to 3.3V when changing the RDP from Level 0 (AA) to Level 1 (DC)
4. [Details]
I flashed a custom secure application with TFM onto the device, but it was not working. I wanted to disable TrustZone and return the chip to a “normal” state. Following AN5347 (Section 9.1.2) and an ST Community post, I attempted to perform a regression.
Everything worked until I set the RDP to Level 1. However, after power-cycling the target, I could no longer connect to the device. Regardless of how I reset the target or change the ST-LINK connection mode (Hotplug, Under Reset, etc.), I only receive errors such as the following:
BOOT0 to VDD:
BOOT0 to the ground:
5. [Expected behavior] I want the chip returns to the "Normal" state.
6. [How to reproduce] Apply the RDP option byte to level 1 (DC) by STM32cubeprogrammer with BOOT0 on high and hotplugging the target.
7. [Occurrence] The chip is bricked.
8. [Sanity checks] Can not connect to the target.
Any help or guidance would be much appreciated.
Lezhi
