I have a device with STM32F429ZT on it, the Read Out Protection of the processor is at level 0. In some cases(somehow it happen I don't know, I saw this situation on 1/7 device), when I reconnect with ST-Link Utility, I see Write Protection turned on. I can turn off write protection, but I could not find the cause of this problem. Any electrical malfunction, short circuit, etc. can something enable write protection?
I reviewed the STM32 security document and read about static and dynamic protections. In dynamic protection, stm32f4 has an MPU, but it is not active in my code.