How to permanently disable j-tag without enabling readout protection level 2?

[PREDATOR]

Need to protect data access through j-tag, but need to program flash through inbuilt boot loader

[dbgarasiya]

it is mostly for temporary . after reset it will automatically enable

[oleksandr.karbivsky]

Hi. If you want permanently disable j-tag, you must develop your own bootloader and set RDP level 2.  In-build bootloader is not 100% safety. It is already hacked.

[PREDATOR]

Is there any other option other than RDP level changing to disable j-tag in stm32?

[oleksandr.karbivsky]

Only RDP level 2 can disable debug access to uC permanently. Other types is easy to hack. Here some info.

What device do you use?

[PREDATOR]

STM32H743ZI

[alister]

You've decided not to RDP level 2.

You next most secure option is to RDP level 1 AND configure your JTAG/SWD pins as GPIO inputs at run-time.

[PREDATOR]

How to find out swd pins in STM32CubeMX?

[PREDATOR]

How to set SWD pins as GPIO pins in STM32H743ZI ?

[Danish1]

Have a look in the Reference Manual for your stm32. I know it is a big and daunting document, but this is where the answers to most questions are most completely given.

In there is a chapter on GPIO. In there you will discover how to set the MODE to be either digital input, digital output, alternate-function or analog input. SWD is one of the alternate-function options.

Hope this helps (I know you'd solve _this_ question more quickly if I just answered _this_ question. But once you know your way around the Reference Manual you won't need to ask us nearly as many questions),

Danish