Full chip erase for signed bootloader and fimware for stm32h757

[developersupport]

I need to flash signed bootloader and signed firmware for ardupilot the file i am using is arducopter_with_bl.hex
after this I need to erase the entire chip and need to flash unsigned bootloader and unsigned
firmware again so that i can use that again. I want to achieve this without bricking the board because once it has happend.
My board does not have BOOt0 pin and it does not have DFU mode. I am using ST-LINK using SWD.
If any body can help me th how to achieve this. Thanks in advance.

[Aziz BRIGUI]

Hello @developersupport,

This request is ambiguous, could you provide further details on why the board risks to be bricked?

Thanks,

Aziz