STM32F765 can use stlink to burn firmware via SWD, but can't access bootloader.

[yushangchen]

I am building a circuit board using STM32F765. After building it I can use stlink to burn the firmware (stm32 utility) via SWD and read the chip correctly, but I can't get into the bootloader and I can't use the serial port (USB) to read the chip on my PC.
Make sure the power supply is normal. I'm not sure what's going on here.

[STOne-32]

Dear @yushangchen ,

Can you give more details with a log when booting from Internal bootloader with BOOT0 pins ? and use the STM32CubeProgrammer either via UART or USB ( DFU).

Some hints :

0) Picture of the top marking and revision

1) Let us know the schematics and especially the  used crystal HSE XXMHz.

2) try to measure the HSI - Internal 16MHz RC used in the internal booloader and output via a code in flash on MCO - PA8 pin.

Hope it helps.

STOne-32.