Resolved! NUCLEO-F429ZI can't go to UART bootloader with the reset button, but only after a power cycle. Why?
I'm using a NUCLEO-F429ZI. It can't go to UART bootloader when using the reset button (BOOT0 connected to 3.3V). It will only go to UART bootloader if I power cycle the board ((BOOT0 connected to 3.3V)). What is going on? It should read the BOOT0 pin...