After trying to Disable Trustzone, no longer able to connect to micro

[GaneshS]

I am trying to disable TrustZone on my MCU - STM32U5 and i followed the steps as per the instructions given here :

https://community.st.com/t5/stm32-mcus/how-to-disable-trustzone-on-stm32u5-series/ta-p/49793

After I uncheck the TZEN option byte, I no longer can connect to the micro 

I get the following error:-

Kindly help 

[Imen.D]

Hello @GaneshS and welcome to the Community 🙂

Did you try with the latest version of CubeProgrammer?

I recommend you following the detailed steps mentioned in the "​9 TrustZone deactivation" section of the AN5347 Arm TrustZone features for STM32L5 and STM32U5 Series application note.

Imen

[GaneshS]

Hello I replicated the steps as given in the app note . I am using the latest version of the programmer ie . 2.15 

Tried logging through the CLI

Does not let me read/write option bytes. What am i missing ? 

[Christian N]

Hello GaneshS ,

Thank you for contacting STMicroelectronics. Your inquiry is being escalated for specialized support.

Kind Regards,

Christian

ST Support