B-U585I-IOT02A TFM_UPDATE.sh reports ST-LINK error (DEV_TARGET_NOT_HALTED)

[NPato]

Hi,

I'm trying to use the TFM (Trusted Firmware M) example application from the B-U585I-IOT02A board. On first attempt the application compiled, flashed (via TFM_UPDATE.sh) and runs. But now I want to make changes to the system and after compiling the changes and running TFM_UPDATE.sh it now says 'ST-LINK error (DEV_TARGET_NOT_HALTED)'. 

Any ideas how to sort this out? Any documentation that might help?

Thanks

Nigel

[NPato]

The TFM example does not seem to provide any info on how to do this but AN5347 does in the section 'TZEN/RDP regression with a boot from RSS'.

With the BOOT0 switch in the '1' position power cycle the board and connect to the board using STM32CubeProgrammer GUI with the 'Mode' set to 'Hot plug'. Once connected set the RDP level to 1, value 'DC' and click 'Apply', it will warn you that your device may become unrecoverable but say ok. Once that is complete uncheck the TZEN option and change the RDP level back down to 0, value 'AA', these must be applied at the same time for it to work, again click 'Apply'. Once that is complete move the BOOT0 switch back to position '0' and power cycle the board. Then from the TFM_SBSFU_Boot project run the regression.sh script followed by the TFM_UPDATE.sh script.