[NUCLEO-L552ZE-Q BD] How to change RDP from 1 to 0

[YKim.30]

Board: NUCLEO-L552ZE-Q with default setup

SW: STM32CubeProgrammer

After changing RDP from 0 to 1, which was my mistake, I can't connect the board with the program, STM32CubeProgrammer. Whenever I tried to connect, it gave me the error, "Error: ST-LINK error (DEV_TARGET_NOT_HALTED)".

I've just found a limitation about RDP for this board in Session 6.3 of the document, STM32L5 Nucleo-144 board (MB1361).

"""

Known limitation:

• Activating the readout protection on the STM32 target prevents the target application from running afterward. The target readout protection must be kept disabled on ST-LINK/V2-1 boards.

"""

Should I buy a new one?

Any ideas would be highly appreciated!

[Bubbles]

Hi @YKim.30​ ,

you can try attaching an ST-link 3.0, which could work, but I haven't tried myself.

BR,

J

[YKim.30]

Hi @JHOUD​ ,

Thanks for your reply. I am somewhat confused about ST link 3.0. What did you mean by 'ST-link 3.0'? Is it this one?

https://www.st.com/en/development-tools/stlink-v3set.html

[Bubbles]

Hi, yes. Or alternatively, as it was with ST-Link 2, now some newer Nucleo boards are equipped with ST-Link 3 which can also be used to debug externally connected devices.

For example Nucleo G491 has such capability.

Rgds,

Jarda

[YKim.30]

I see, but on the board I have, it supports only ST-Link 2.1. Is it not possible to retrieve

the RDP value from 1 to 0 with ST-Link 2.1?

[YKim.30]

For your information, I followed the instruction from https://wiki.stmicroelectronics.cn/stm32mcu/wiki/Security:How_to_disable_TrustZone_in_STM32L5xx_devices_during_development_phase, after setting RDP level to 1 in step2, I can't connect the board with the tool STM32CubeProgrammer. It keeps giving me an error "DEV_TARGET_NOT_HALTED" or "Error: Uploading Option Bytes bank: 0 failed" "Error: Initializing the Option Bytes failed".

I might need to use the different power supply, but I am not entire sure how to change it. In my case, I tried to use 5V_STLK, 5V_USB, or 5V_CHGR in JP6, with the USB-B (CN1) and the USB-C (USB1), but all of them didn't work.

[Sara BEN HADJ YAHYA]

Hello @YKim.30​ ,

Please check section 7 in this AN5347, it might help.

If your issue is solved, please close this post by clicking the "Select as Best" button. This will help other members of the community find this response more quickly ��

Sara.

[YKim.30]

I've already seen the document, but I couldn't do anything with this board if I understood correctly. I might need to buy either other boards or ST-Link 3 to make it work. In any case, I don't understand why this happens even though I followed the instruction in the official blog. It should be clearly described that we MUST NOT try to disable Trustzone after enabling it.