Trying to understand a bit more about the bootloader with the stm32f chips. Is the dfu bootloader written to 0x1fff? When I use the boot reset 0,1 mode it does work and the data sheet says it boots to 0x1fff. So I believe this is correct.
In talking to Keil support it was mentioned that a bootloader like dfu had to be written to 0x08000000. However when I write a project to the chip occupying 0x08000000-0x08003000 the bootlaoder remains intact. I'm guessing Keil support was incorrect in this case.
If this is true and the dfu is written to 0x1fff, is there a uvision project that I can sample from that writes the bootloader to the chip? In my cause it arrived this was from a waveshare kit.
The System Loader on STM32 parts is located in "ROM", you can neither write nor replace it.
Depending on the model, the BOOT pins control the memory shadowed at zero, and thus booted by the processor. The STM32F2/4 parts have the ROM situated at 0x1FFF0000
You could implement your *own* DFU loader, and that would need to be situated at 0x08000000, as that's the memory available to you.
That explains things, Keil must have though I was referring to a custom bootloader. Thank you.