ESP32 Forum

By default, in many MCUs, watchdog's and BOD's are disabled by default and are required to activate them in the software. If this is true, this must be done as soon as possible after powering the MCU.

However, what happens if the MCU crashes because of power or any random reason BEFORE the bootloader(?) Activates them? Will it be freezed forever? How to solve this (if true) without external hardware? In IDF 3.2, has API to use rtc_wdt but in rare cases when I floating power supply during boot, esp freeze... How solve?

On the ESP32, the WDT is enabled from hardware boot-up. The boot-up process does some work to switch from what the hardware leaves us with to something more suitable to a RTOS, but in general you should always have some form of WDT protection. The BOD is not enabled by default, and only gets enabled at some point in the boot process; we know this is a shortcoming of the BOD. If you need rock-hard BOD protection, we advise to go with an external reset generator / BOD.