Cannot upload bootloader via USB port (DFU), but no problem via ST-LINK

[EThom.3]

Where to start...

I have mave made a bootloader (done this before), which is placed in the low end of the flash memory. The application is in the subsequent flash.

My board has a USB port and a DIP switch for forcing the BOOT input pin high. When I flip the DIP switch on, and power the board, I can connect STM32CubeProgrammer to the internal DFU bootloader via the USB port. I can also upload my application through the USB port. But when I try to upload my own bootloader, it fails. This is the output from STM32CubeProgrammer:

However, if I connect an ST-LINK programmer to the board, I can upload the very same file with no issues. Output from STM32CubeProgrammer:

Clearly, something starts to go wrong at "Not flash Memory: No erase done"

Just now, I upgraded STM32CubeProgrammer to the latest version (2.21.0), but this made no difference.

But why does it work with the ST-LINK programmer, and not through the USB port? And why can I upload the application through the USB port, but not the bootloader?

Can it have something to do with the bootloader using segments 0, 1 and 3, but not segment 2? Does the DFU bootloader dislike such things?

[Mike_ST]

Hello,

Not sure, but,

The elf file you're trying to upload probably contains a segment outside of the flash range, probably RAM (0x2000235C).

The ST-link debugger seems to be able to write into RAM, but the internal bootloader not, it seems to be able to write to the flash only.

I would try to check the linker file to output a binary in the flash address range or process the elf file to keep only the flash part.

[EThom.3]

Hi Mike,

That's interesting. I wonder why the elf file would contain data that belongs in RAM.

Thanks a lot. Will look into it.

[EThom.3]

Problem solved. It would seem that the sections in the linker script were in the wrong order. After I moved the sections I added (.idsection and .uninit_data) to other positions in the file, the linker no longer tries to add the user heap to the .elf file.

@Mike_ST thank you for the tip with the linker file.