Hi I think my DFU Bootloader code in my STMF407VET6 i corrupted. Nothing happens when I pull BOOT0 high and start the device. Look at the attached screenshot. Is it supposed to look like this?

[LNerg.1]

[TDK]

No, it shouldn't look like that.

You're using the programmer on the nucleo board to connect to an external custom board?

If you can otherwise use the chip by programming/reading/erasing the flash and it behaves as expected, perhaps you have a dud chip. Perhaps a half-baked clone.

[LNerg.1]

Yes, using nucleo externaly.

I can program the chip and add applications to 0x08000000.

Is it possible to flash the bootloader binaries over or is the chip dead?

[TDK]

The bootloader is in ROM and cannot be modified in any way. This also means it cannot have been erased.

[TDK]

If I were you, I would read out values around 0x1FFF0000 within my code to double check what STM32CubeProgrammer is telling me.